CN1185838A - Electronic metering device with automatic service sensor - Google Patents

Abstract

An integral electronic meter system diagnostic package including a microprocessor, storage memory, pre-select series of system diagnostic tests and recording any results which exceed predefined programmable thresholds, and display means for displaying error and/or diagnostic messages identifying selected diagnostic data and/or errors discovered in the meter tests during a predefined period. The system automatically senses the type of electrical service in which the meter is installed.

Description

Band is safeguarded the electric measuring instrument of sensing apparatus automatically

The application is that the sequence number of on March 26th, 1993 application is the part continuation application of 08/037,938 " system of electric measuring instrument detects and fail analysis device ".

The a whole set of method and apparatus of diagnosis is installed by the system that the present invention relates to carry out solid-state electric measuring instrument.

The induction type watthour meter is general adopts a pulse producer to produce and the proportional pulse of dial plate rotating speed.With the pulse of these generations be sent to electronic recorder obtain electric current, voltage, power and/or use power consumption time.

Nowadays various types of solid-state heterogeneous electric measuring instruments also are being extensive use of.This instrument monitoring power consumption and with kilowatt-hour, power factor (KVA) and (or) var writes down or reports this power consumption, the general solid-state module that adopts, and can utilize analog-digital converter that numerical data is provided, rather than pulse data, indicator can extract various demand/consumptions from these data.

People also know can install reconfigurable solid-state electric measuring instrument in various single-phase or heterogeneous distribution systems.At the No.5 that licenses to people such as Germer, disclosed a kind of example of solid-state electronic watthour meter in 059,896 United States Patent (USP).

Licensing to the No.4 of Swanson, disclosed in 697,182 United States Patent (USP)s a kind of can with the example of the common solid-state need for electricity amount register (electricity demand recorder) that uses of conventional watthour meter.

In the installation process of these ammeters, the maintainer utilizes various utility appliance and diagnostic techniques to strive to corroborate installation correctly wiring.Yet the many installation and measurings that resemble polarity and cross-phase detection and so on are carried out then and there by the field staff, thereby depend on these people's knowledge and ability.

As various diagnostic devices installing for the field staff or periodically safeguard during when using, just proposed do not interrupting carrying out automatically periodically under the ammeter ruuning situation demand of a standard series system with the corollary apparatus that diagnosis is installed.In addition, also be necessary to make ammeter to be in operation periodically self-check to measure the also fatal or not appearance of critical failure of recording scheduled justice.

In addition, though more existing can be adapted at the ammeter that more than one type of electrical are used in safeguarding, the shortcoming of this class ammeter is that the user usually must enroll before installing and safeguards type.Polymorphic type safeguards that this pre-installation programming of ammeter certainly will limit the ability that their polymorphic types are safeguarded.

In view of this, the objective of the invention is to provide the complete system of a cover to detect and fail analysis device for solid-state electric measuring instrument.

Another object of the present invention provides that a kind of and solid-state ammeter integrates and it is automatically performed a series of predetermined systems install and the method and apparatus of diagnostic test.

A further object of the invention provides a kind of system that supports and be integrated in the electric measuring instrument and detects and fail analysis device, also comprises the device that is used for showing selected self-check and system diagnostics test result when the maintainer inquires about.

The present invention also has another purpose to provide a kind of automatic system detecting device, periodically detects the existence of some predetermined state, and responds in the predetermined action of any this class fault detect according to the character of fault.

Another object of the present invention provides a kind of method and apparatus of each voltage and current phase vector with respect to the phasing degree of a predetermined benchmark phase vector that be used for measuring, and its objective is that all meter units of checking are all at sensing and each the correct voltage and current mutually that receives heterogeneous electricity maintenance.

The present invention also has another purpose to provide that a kind of and solid-state polymorphic type safeguards that ammeter combines and the back is installed and periodically detects the method and apparatus that electricity is safeguarded particular type automatically at its run duration at ammeter.

According to the present invention, a kind of complete electric measuring instrument self-check and system diagnostics device are provided, comprise a microprocessor, storer, be used for carrying out automatically periodically a whole set of instrument self-check of pre-selected and the logical circuit of any fault that record is taken place, be used for carrying out automatically periodically the system diagnostics test of a series of pre-selected and the logical circuit that record surpasses any result of predetermined programmable threshold, and the display device that is used for showing fault and diagnostic message, these information are represented one or more faults of checking oneself respectively, or selected diagnostic data and/or the fault of in a predetermined period, finding in the instrument self-check.

Apparatus of the present invention preferably combine with the solid-state ammeter that adopts D-A converter and correlated digital Sampling techniques, with a phase of the single-phase or multiphase system that obtains being connected corresponding to this ammeter or the numerical data of polyphase current and voltage.

The present invention carries out previously selected ammeter self-check automatically, preferably every day and (or) when restarting after having a power failure and (or) check once when whole ammeter structure is reconfigured so that verify the operating capability of selected ammeter assembly.For example, in a preferred embodiment, whether selected register in apparatus of the present invention detection its storer, microprocessor and the ammeter worsens so that measure from the data (billing data) of being kept accounts since the inspection last time.Because the data corruption of keeping accounts is considered to the fatal error of ammeter, apparatus of the present invention will produce and show the failure code of an indication fault type, demonstration is locked on the failure code, and ends all ammeter functions (except that communication function), up to this table is reconfigured.

In addition, this device is also periodically checked the non-critical fault that other resemble that the register spill-over goes out, clock, service time, backward power stream and battery are low excessively and so on.The frequency of trouble shooting can change, and on checked parts and state and this fault the potential impact that ammeter continues operation is decided.In case after finding, non-critical fault can depend on how the character of fault and this specific ammeter set up with showing locking.

The present invention also carries out a series of previously selected system diagnostics tests periodically.This class testing carries out when ammeter is installed, and tests once about the preferably every five seconds of ammeter normal operation period.In a preferred embodiment, this device carries out polarity, cross-phase and can flow diagnosis, phase voltage and depart from diagnosis, the diagnosis of idle phase current, the diagnosis of every power factor mutually and current waveform distortion and survey diagnosis, this class diagnosis is that the parameter that utilizes definite parameter of producer and user to determine carries out, and these parameters can be set when mounted by the field staff.

In carrying out the diagnosis of polarity, cross-phase and energy stream, the electric current of device utilization accumulative total of the present invention and information of voltage decide the (V for example of each voltage and current phase vector in the multiphase system _B, V _C, I _A, I _BAnd I _C) with respect to reference phase vector (V for example _A) phase angle.Each phase vector is predefined to the normal position of this installation, and compares as the phase angle of standard value and calculating, to determine whether each phase angle drops within the preset range.If the phase angle of arbitrary calculating drops on outside its corresponding preset range, will show a tracing trouble information.This diagnosis is particularly useful when mounted, because this fault can be pointed out the anti-phase of polarity incorrect, single-phase or heterogeneous (producing jointly) of cross-phase relation, voltage or the current return of voltage or current return and can flow, or inner ammeter surveying work is undesired.

Device of the present invention also shows particularly including a kind of " Toolbox " (tool box), when field staff's start-up by hand, it is examined the whole preset value inventory of roll display for the field staff, as the voltage and current of every phase, the phase angle relevant with each voltage and current phase vector, and every kind of number of times that the diagnosis inefficacy occurs.

In one embodiment of the invention, apparatus of the present invention are after ammeter installs and powers up, particularly periodically in the ammeter normal operation period type safeguarded of sensing electricity (promptly single-phase, three thread triangles, four line Y shapes or four thread triangles) automatically.

These system diagnosticss, tool box show and safeguard that automatically sensing function is carried out under the situation of not interrupting the ammeter operation by apparatus of the present invention, unless have a mind to end owing to a kind of fatal fault makes the ammeter operation.

To going through of implementing that best way of the present invention does, readily understand the above purpose of the present invention and other purposes, characteristics and advantage from reference to the accompanying drawings.

Fig. 1 is a system block diagram;

Fig. 2 is the ammeter three-dimensional view that system of the present invention can make up with it;

Fig. 3 is the block scheme of Fig. 2 ammeter;

Fig. 4 is the process flow diagram of electric system diagnostic detection of the present invention;

Fig. 5 is polarity, cross-phase of being realized by the present invention and the process flow diagram that can flow the first that diagnoses;

Fig. 6 is polarity, cross-phase of being realized by the present invention and the process flow diagram that can flow the second portion of diagnosing;

Fig. 7 is the process flow diagram that is departed from the first of diagnostic routine by the phase voltage that the present invention realizes;

Fig. 8 is the process flow diagram that is departed from the second portion of diagnosis by the phase voltage that the present invention realizes;

Fig. 9 is first's process flow diagram of being diagnosed by the idle phase current that the present invention realizes;

Figure 10 is the process flow diagram by the second portion of the idle phase current diagnosis of the present invention's realization;

Figure 11 is the process flow diagram by the first of every phase power factor diagnosis of the present invention's realization;

Figure 12 is the process flow diagram by the second portion of every phase power factor diagnosis of the present invention's realization;

Figure 13 is the process flow diagram by the third part of every phase power factor diagnosis of the present invention's realization;

Figure 14 is the project list that is presented in the Toolbox demonstration;

Figure 15 is used for the phasor diagram that typical three-phase kilowatt-hour meter is installed;

Figure 16 is the waveform relationship figure of two phasors of explanation representative system tracking:

Figure 17 A is the first of front-end module 42 block schemes among Fig. 3;

Figure 17 B is the second portion of front-end module 42 block schemes among Fig. 3;

Figure 18 A is the first of register module 48 block schemes among Fig. 3;

Figure 17 B is the second portion of register module 48 block schemes among Fig. 3;

Figure 19 is the first pass figure that is surveyed diagnosis by the current waveform distortion that the present invention realizes;

Figure 20 is second process flow diagram of being surveyed diagnosis by the current waveform distortion that the present invention realizes;

Figure 21 illustrates the type list of representing ammeter symbolic vector and supported associated electrical thereof to safeguard;

Figure 22 is the automatic process flow diagram of being realized by the present invention of safeguarding the first of sensing function;

Figure 23 is the automatic process flow diagram of being realized by the present invention of safeguarding the second portion of sensing function.

With reference to Fig. 1,20 the system of the present invention of totally being expressed as comprises a center processing unit 22, be enough to store respectively with the storer 24 of corresponding numerical data that the voltage and current cycle data of voltage A/D transducer 26 and electric current A/D transducer 28 is sampled, be used for carrying out the logical circuit 30 that the ammeter self-check supported by system and system and installation are diagnosed, and the display device that is used for showing fault and diagnostic message.

With reference to Fig. 2, system 20 preferably incorporates solid-state heterogeneous kilowatt/kilowatt-hour (" Kw/Kwh ") single function ammeter 34 (as the diagram of Fig. 3,17A-B and 18A-B and the detailed description of back) into, and this ammeter comprises that a common moulded plastic shell (not showing out) and a table that is roughly circular pedestal 36, band fixed panel covers 40.Ammeter 34 tables also contain the suitable conventional current sensing part that is connected with existing electric system.

Referring now to the Fig. 3 in the preferred embodiment, the front-end module 42 of the diagnostic logic circuit 30 of system 20 of the present invention being incorporated into ammeter, this front-end module comprises a microprocessor 44,8 A/D transducers as voltage A/D transducer 26, the random access memory 45 as system storage 24 parts, and ROM (read-only memory) and EEPROM, the system diagnostics logical circuit just is arranged on here (46).Front-end module is except being shown with installation diagnosis and tool box by 20 performed systems of system of the present invention.Other ammeter function also preferably is provided, comprises the self-check of ammeter parts, A/D sampling, energy calculating, current demand, instantaneous value, any optional output, and ammeter communication.Display in the present embodiment is a kind of LCD 33, it preferably contains 9 seven hop count positions, 3 decade points and is used to show the power system information that usually shown by conventional ammeter and by a plurality of icons of the diagnostic data that system of the present invention produced, substantially as shown in Figure 3.

Ammeter 34 also comprises a register module 48 that microprocessor 50 is arranged, and comprising: ROM (read-only memory); Random access memory 51, it is simultaneously partly as system storage; 96 sections LCD display drivers; And 24 I/O lines.In this embodiment, ROM (read-only memory) and register CPU50 comprise and are used for producing the display logic circuit that the tool box shows and have the diagnostic trouble code (DTC) that system 20 of the present invention produces.Register module 48 resembles from reading, the time correlation function that service time, working time and high capacity storage are such, other ammeter functions also being provided, as keeping record keeping value and record keeping register correlation function except comprising.

Should be noted that in the embodiment of ammeter 34 shown in Figure 3 system of the present invention 20 uses 8 byte A/D transducers 26 that are used for the sensing voltage signal and one to be used for the outside 12 byte A/D transducers 28 of current sensor sampling.Known to those of skill in the art, because the scope that electric current changes is wideer than voltage, the resolution characteristic that power pack 28 is had relatively high expectations.These those of skill in the art also can understand best by the transducer that separates next current sensor and voltage simultaneously, so that the phase error that current transformer produces can directly compensate by the time-delay of adjusting between current sample and the voltage sample.Therefore, at desirable current transformer and do not transmit under the phase delay situation, then available independently transducer 26 and 28 pairs of voltage and currents are sampled simultaneously.

Be used for that the tool box of generation system 20 shows and the display logic circuit of tracing trouble information is by the part of the display logic circuit 52 of register CPU 50 realizations in Fig. 3 specific embodiment.Yet those of skill in the art can understand, the logical circuit of system of the present invention and the ability of CPU can realize with a kind of better simply signal processor structure (as shown in Figure 1) and structure shown in Figure 3 or other hardware facilities and not depart from essence of the present invention.

System 20 of the present invention shows by " tool box " provides FR system diagnostics ability and diagnosis Presentation Function.This system is partly determined by programming software by the user with the installation diagnosis.This tool box is a kind of demonstration that is included in the diagnostic message that fixedly installs in the concrete method of operation, and it can come access by the magnetic switch that user's (generally being the field staff) starts on the ammeter.To further go through every kind of diagnosis capability below.

In one embodiment, system 20 also provides a kind of automatic sensing function of safeguarding.As below will describing in further detail, this ability comprises and be used for measuring automatically periodically the logical circuit that ammeter provides electricity to safeguard, and is this when being determined at ammeter and installing, power up the back and the angular displacement of the form of periodically programming in advance according to ammeter at the ammeter run duration number and voltage phase vector Va and Vc is carried out.As described below.System and installation diagnosis

System 20 of the present invention finishes multiple systems and diagnosis is installed, and can indicate and the mistake installation of electricity maintenance, ammeter or the undesired relevant potential problems of function of ammeter inside.Though the diagnosis of this class may be safeguarded type and change that following diagnosis is generally finished by this system by the electricity that ammeter provided.

With reference to Fig. 4, this system realizes as a kind of status mechanism with the installation diagnosis is also best.In the preferred embodiment, diagnosis can be made up of four kinds of diagnosis that ammeter is selected to carry out the user: (1) polarity, cross-phase and can flow inspection; (2) phase voltage departs from inspection; (3) current transformer inspection; (4) every phase power factor is checked; And the distortion of (5) current waveform is checked.All chosen diagnosis are undertaken once by per at least 5 sampling interval of ammeter.

When any malfunction appears in the parameter of determining corresponding to the diagnosis inefficacy according to the user, the ammeter display message indicates its malfunction, and trigger an output contact selectively and close, soak into relay or a solid-state contact that is programmed for " malfunction warning " as a mercury.When the output of a selection was programmed to the malfunction warning, in case any tracing trouble of being selected by the user is triggered, this output contact will be closed at any time.

Refer again to Fig. 4, system 20 of the present invention preferably illustrates by series of computation shown in the 54-62 and deagnostic test.In this preferred embodiment, will be divided into the sampling interval that equals 60 power circuit clock period the processing time.For example, in the equipment of 50Hz, this is 1.2 seconds.In the equipment of 60Hz, sampling interval will be 1 second.

With a simple counter,, system 20 carries out necessary sampling and calculates to determine I _APhase angle (preferably with respect to phase vector V _A), and in first sampling interval, carry out deagnostic test #1, shown in 54.

At second interval (56), I is calculated in system's necessary sampling of 20 accumulation _BPhase angle and carry out deagnostic test #2.

At the 3rd interval (58), I is calculated in system's necessary sampling of accumulation _CPhase angle and carry out deagnostic test #3.

At the 4th interval (60), V is calculated in system's necessary sampling of accumulation _BPhase angle and carry out deagnostic test #4.

At the 5th interval (62), V is calculated in system's necessary sampling of accumulation _CPhase angle, carry out deagnostic test #5 and with counter zero setting.

The end counter was added for 1 (64 step) at interval at each, and its order repeats continuously.Like this, in the 60Hz system, each electric current and voltage phase vector are calculated its phasing degree, and carry out four kinds of deagnostic tests each, per 5 seconds once.Known to those of skill in the art, the different time intervals can be carried out and/or subroutine 54-62 can be changed, adapt to one or more more frequent or not frequent inspections by the selected diagnosis of hope.Diagnose #1-polarity, cross-phase and can flow inspection

Press Fig. 5 and 6, polarity, cross-phase and flowing checked to design and checked that any phase voltage and current polarity are reverse, and check the false wiring of certain phase voltage and out-of-phase current.This situation also may produce because of the appearance of resonance.This inspection is by measuring each voltage and current phase vector periodically with respect to reference vector (V preferably _A) phase angle finish.Each phase angle phase angle desirable with it compared, and the latter is defined as from an issuable phase angle of the pure resistive load of balance.Surpass predetermined value (best 10 °) if any voltage phase angle lags behind or leads over its desirable phase angle, or any electric current phase angular lag or leading its desirable phase angle surpass second predetermined value (best 90 °), then a diagnosis of ammeter indication #1 fault.

As shown in Figure 5, the polarity of system 20, cross-phase and flowing checks that diagnostic routine 66 at first checks each phase angle (being applicable to the particular power system that is connected to ammeter) of each electric current and voltage phase vector (at 68-76 place), determines whether each phase angle drops in the tolerance limit of the predetermined ideal value that ABC is rotated.If any of these phase angles do not drop in the allowed band of ideal value, then the abc of this system indicates and is set to mistake (at 78 places), is assumed to the CBA rotation again, sets about (as shown in Figure 6) and checks each phase angle.

If all phase angles of measuring via 68-76 all drop in the allowed band of its predetermined ideal value, then system 20 indicates at 80 abc of place and is set to correct (80 place), and hand inspection be assumed to the phasing degree of cba rotation.

With reference now to Fig. 6,, in case after carrying out ABC rotation inspection, whether system measures the phase angle that rotates for CBA and drop in the allowed band of its predetermined ideal value via the phase angle that 82-90 checks each electric current and voltage phase vector.If arbitrary phasing degree is dropped on outside the allowed band of that phase vector predetermined ideal value, system indicates at 92 cba of place and is set to mistake.If all phase angles of measuring all drop in the allowed band of its predetermined ideal value, then system indicates at 94 cba of place and is set to correctly.Then, system 20 determines whether that abc still be that cba indicates is correct.If the both is correct, then deagnostic test just passes through.If abc indicates and cba sign both is incorrect, then to rotate both deagnostic tests all substandard for ABC and CBA, indicates a tracing trouble.

When measuring a tracing trouble, the appearance of system log (SYSLOG) fault also demonstrates this fault, and the back further describes again.But in this preferred embodiment, all exist this malfunction the initial demonstration of this tracing trouble also not occur up to three continuous review.

Known to those of skill in the art, this diagnosis can be pointed out in some problem, comprises the cross-phase relation of current potential or current return, the incorrect polarity of current potential or current return, and a phase or heterogeneous reverse energy stream or inner ammeter surveying work are undesired.Diagnosis #2-phase voltage departs from inspection

Refer now to Fig. 7 and 8, design this phase voltage and depart to check it is in order to determine that to being in the user any phase voltage outside the scope checks (at 98 places).This is actually the inspection of a kind of substation transformer voltage gap.This is by the predetermined voltage range of measuring the demarcation of every phase voltage and follow procedure software periodically it to be checked to finish.

This checks that used formula is: $V_{\mathrm{upper}}=(1+\frac{\mathrm{XX}}{100})V_A,$ And $V_{\mathrm{lower}}=(1-\frac{\mathrm{XX}}{100})V_A$

If arbitrary phase voltage is higher than V _UpperOr be lower than V _Lower, ammeter will be indicated a phase voltage scope tracing trouble.

Should be noted in the discussion above that in this preferred embodiment system 20 checks (at 100 places) are that the electricity that ammeter supported that will measure the system of being equipped with 20 safeguards to be that a kind of three-phase, four line Δ connections are safeguarded.If like this, the upper and lower bound of C phase voltage particular case just calculates in system, shown in 102.

In addition, if C phase or B phase voltage surpass preset range, system indicates current deagnostic test to lose efficacy at (at 104 or 106 places), points out a tracing trouble, writes down this fault and demonstrates corresponding failure message, as hereinafter described.Otherwise current deagnostic test is just by (at 108 places), and this detects promptly to accuse and finishes.

But it should be noted, in this preferred embodiment, all exist this malfunction the first demonstration of this tracing trouble just to occur up to three continuous review.

This diagnosis can be pointed out transformation ratio, the Transformer Winding short circuit of the loss of phase current potential, mistake, and incorrect phase voltage, inner ammeter are measured problem undesired and that other are potential.The idle phase current inspection of diagnosis #3-

Referring now to Fig. 9 and 10,, in carrying out idle phase current diagnosis, system 20 will compare every mutually instantaneous RMS electric current and the minimum current level of being scheduled to periodically, and it is optional from 5mA to 200A that its scope is preferably pressed increment 1mA.If all three-phase currents are all more than enable level, or all three-phase currents are all below enable level, then this time diagnosis is just passed through.Any other combination all will cause diagnosing #3 substandard, and will indicate a diagnosis #3 fault.

Yet, had better all exist this malfunction the record and the demonstration of this tracing trouble just to occur up to three continuous review.

The appearance of diagnosis #3 fault means a phase or polyphase meter phase current magnitude discord specification.In order to solve this particular problem, the user must obtain phase current information from the Toolbox pattern.As described later.

Known to those of skill in the art, this deagnostic test can be used to refer to any one in some potential problems, for example the open circuit or the current transformer circuit of short circuit.The every phase power factor of diagnosis #4-is checked

Referring to Figure 11-13, design is every-and phase power factor deagnostic test is in order to verify whether the phase angle between every phase current phase vector of ammeter and the desired voltage phase vector is in the scope of user's appointment (+/-1-90 °).Because the restriction of this tolerance comparison diagnosis #1 is bigger, system 20 carries out this deagnostic test by the side up to diagnosis #1.This diagnosis may be pointed out any of a series of potential problems, comprises bad power-factor of load state, bad system state or abnormal system equipment of working.

System 20 checks at 114 and 116 places that earlier abc and cba rotation indicates, and is all wrong as these two kinds of signs, and expression diagnosis #1 lost efficacy.Because the tolerance of this diagnosis comparison diagnosis #1 restriction is bigger, this deagnostic test is ended.

If abc and cba sign all are correct (expression diagnosis #1 passes through), system 20 carries out corresponding ABC and CBA rotation respectively and checks at 114 and 116 places.To ABC rotation, phase angle (118-122) between corresponding electric current phase vector of systems inspection and the desired voltage phase vector, whether be in the scope that the user determines to determine this phase angle.If this phase angle is in the predetermined scope, diagnosis this time is just by (124 place).If not, then this time diagnosis was lost efficacy (126), pointed out a diagnosis #4 fault.Under CBA rotation situation, 20 pairs of electric current phase vectors applicatory of system are carried out the inspection (128-132) of similar scope.The distortion of diagnosis #5-current waveform is checked

Referring to Figure 19, design current wave form distortion inspection is in order to detect any one existence of middle DC electric current mutually.This diagnosis is particularly useful to the ammeter that is designed to the stream of indirect current only, and the performance of this current transformer is degenerated because of excessive DC current, because of DC current makes the mutual inductor biasing, causes it to be operated in the inelastic region.

The basic skills that produces DC current in ammeter is half-wave rectification load in parallel on normal load.The existence of half-wave rectified current signal has and improves the positive half cycle of waveform or negative half period amplitude and keep the impregnable effect of another half cycle.Be not designed to the ammeter of perfectly straight stream electric current for those, when sort signal appeared at the input end of current transformer, its level floats and makes output mean value was zero.Yet the peak value size of the positive and negative half cycle of waveform is no longer identical.The direct current detection diagnosis utilizes this phenomenon by get positive and negative peak difference in a sampling interval of ammeter.If there is not DC current to exist, the result that current sample adds up in an interval should be one and approach zero value.As having DC current, then long-pending evaluation will significantly raise.No matter how are the phase place of the AC current waveform of following and amplitude, this method (referring to following Comb Filter method) is always provide exact value.

Since adopting ammeter of the present invention generally is polyphase meter, mean two-phase or three-phase current that existence is measured by this table, some people half-wave rectifying circuit of cross-over connection in load is distorted ammeter and with the DC current introducing equipment.This circuit can be added in certain single-phase on.For this reason, DC detects diagnosis and should be able to detect DC current in the biasing mutually every.

The Comb Filter method of calculating every phase direct current detection value illustrates in the process flow diagram of Figure 19.This method comprises the steps: in each sampling interval

(1) the record each is every the symbol of interior first voltage sample;

(2) utilize the symbol of first voltage sample, detect first voltage of zero passage;

(3) second sample rate current behind the voltage zero-cross is accumulated to (about 90 °) in the current peak totalizer;

(4) per the 4th current sample in initial current sampling back is accumulated in the current peak totalizer (is separated by about 180 °);

(5) repeating step 4; And

(6) finally, will add up current peak divided by used suitable current value in this interval in sampling interval.Its effect is the normalization as a result of three different gains scopes will electric current being existed.Simultaneously, be the totalizer zero clearing of next sampling interval.

The result that step 6 is divided by is proportional to dimensionless number of this phase DC current.This value will be called the DC detected value.The detection threshold of DC detected value and pre-selected is compared, to determine whether DC current may exist.In the present embodiment, detection threshold is made as 3,000, is to 200 amperes and 20 amperes of two kinds of threshold values that ammeter all is fit to because have been found that 3,000 these values.

This diagnosis utilizes A/D to sample to determine the voltage and current of every phase, and sampling is 481 times in each sampling interval (being generally 1 second).Every phase current has associated gain.If current magnitude variation is enough fast, then this gain of each sampling interval may change.This point is important in direct current detection, because detection technique requires in the section sample rate current value is being sued for peace sometime.As the select time cycle greater than sampling interval, then the summation of the current value this possibility of sampling that is included in the different gains scope exists, so just the sampling that adds up loses its meaning.Therefore, be important with used suitable current gain in each sampling interval with the normalization of gained sample rate current peak value, as described in top step (6).

It should be noted that the calculating of DC detected value will only carry out one mutually in arbitrary single sampling interval.Therefore, different with other those diagnosis of carrying out once by per at least 5 sampling interval of ammeter (being generally per 5 seconds), each of possible three-phase current is carried out three continuous review mutually, be spaced apart 5 seconds, always the sampling time is every phase 15 seconds.Required T.T. of like this, once complete current waveform deagnostic test is 45 seconds (an A phase, B mutually and C respectively 15 seconds mutually).

If find DC detected value to all three consecutive intervals of a specific phase, just write down on mutually and have DC current at that all greater than selected detection threshold.After all three-phases are all checked, if go up mutually the DC current record is arranged all any one, then diagnosis starts.Went up mutually at interval later and any one when 45 seconds and not find that all when undesired, then diagnosis will be closed.

It should be noted that and detection threshold should be arranged on the DC current level that the current transformer corresponding to ammeter begins to worsen, so that before this DC level arrives, can detect fault with record diagnosis #5.

Referring to Figure 20, this diagnosis is called the phase shift inspection program three times to each phase of three-phase electricity.The phase shift inspection program is adding up current sample, the sampled data that will add up normalization and this value stored as a direct current detected value DVn three sampling interval of this phase each time then.

Refer again to Figure 19, check diagnosis #5 program at 200 places by remove at interval reading and A mutually, B mutually and C each fault reading (PHA ERRCT, PHB ERRCT and PHCERRCT) beginning mutually, interval counter can be mould 9 counters, its increment size can be 0-8, returns 0 then, or the like.At three 5 seconds each at interval every (promptly counting=0,1 and 2 at interval), program is checked A phase excute phase at 202 places, in ensuing three 5 seconds intervals (promptly counting=3,4 and 5 at interval), program is checked B phase excute phase at 204 places, for last three 5 seconds intervals (promptly counting=6,7 and 8 at interval) of 45 seconds interval between diagnosis, program is checked C phase excute phase at 206 places.

In case finish each the phase shift inspection program to the A phase, whether system just determines the DC detected value greater than detection threshold at 208 places, and if this DC detected value greater than detection threshold, then A phase fault counter (A phase ERRCT) is value added.Then B is called the phase shift inspection program three times mutually.After every phase scrutiny program was finished, system 20 detected the DC detected value once more and whether greater than detection threshold B phase fault counter (B phase ERRCT) is set correspondingly also at 210 places.And then C called the phase shift inspection program mutually, system 20 will compare from DC detected value and the detection threshold that C obtains mutually once more at 212 places, and correspondingly value added to C phase fault counter (C phase ERRCT).

Next system 214 places determine A phase, B mutually and C mutually in the failure counter of arbitrary phase whether equal 3.If equal 3, during three continuous sampling, that is met and detect the DC electric current, system just at 216 places to each phase of ERRCT=3, promptly A phase, B mutually and C failure counter mutually indicate a diagnosis #5 lost efficacy (being respectively PHA CHK FAILURE, PHB CHKFAILURE or PHC CHK FAILURE).Under any circumstance, each PHA, PHB and PHC CHK FAILURE count value are added to diagnosis #5 counter (expression diagnosis #5 fault cumulative total), diagnosis is promptly accused and is finished.

So, unfinished 45 seconds sampling interval, after every phase current is checked three times,, then will write down and once diagnose the #5 fault if any one of three-phase fault counter all write down fault in all three times are checked.The diagnosis #5 counter of reporting in Tool Box pattern (DIAG#5 ERRORCOUNTER) is exactly these three every phase DC detection counter sums.Automatically safeguard sensing

In one embodiment of the invention, system comprises and is used for measuring the logical circuit that the electricity supported by ammeter is safeguarded automatically according to the angular displacement of the pre-programmed form factor of ammeter and voltage vector Va and Vc.This performance has been cancelled to be needed electricity is safeguarded that type is programmed into the requirement of ammeter before installation to the user, thus allow the user make full use of this ammeter flexibly, the ability safeguarded of polymorphic type, and reduce user's ammeter catalogue requirement.In addition, automatically electricity safeguards that sensing function guarantees ammeter and any enabled systems and diagnosis is installed all will correctly moves after installing with minimum pre-programmed.At last, safeguard that automatically sensing function allows ammeter to safeguard that from a kind of electricity reinstalling to another kind of electricity safeguards, and need not the electricity that ammeter supports is safeguarded the change pre-programmed of type.

Referring to Figure 21, in one embodiment, it is that a kind of automatic electricity of those ammeters of form 5S, 6S, 9S, 12S, 16S, 26S, 5A, 6A, 8A and 10A is safeguarded sensing function that this system comprises pre-programmed.Every kind of different maintenance of one of form group shown in Figure 19 has unique balance resistance load vector figure, shows each single phase current and the mutually angular range of voltage with respect to the A phase voltage.In the application of a practical field, the electric current phase vector will move apart these balance resistance load situations because of the variation of load.Yet the voltage phase vector can not change with load, and should be in 1 ° of its balance resistance load situation or the 2 ° of scopes.Because B phase voltage vector neither occurs on two yuan of ammeters, can in 6S (6A) ammeter, not exist yet, this voltage is to design usefulness.Yet C phase voltage vector all exists all different forms and maintenance, and measures with respect to the A phase voltage.So,, only provide with respect to the inspection of the C phase voltage azimuth position of A phase voltage vector and to determine which kind of ammeter is in and safeguards required information the form ammeter that is marked among Figure 21.

The unique exception of this rule is that network is safeguarded and can not be distinguished with A phase voltage vector position mutually by simple inspection C in 5S, 26S form group with four line Y shapes.In the example of said system, system supposes that simply a kind of four line Y shapes are under these conditions safeguarded.

Like this, as shown in figure 21, if the form factor of known ammeter, then the type of electricity maintenance usually can be determined by the angular displacement of measuring voltage vector.In fact, each form is that the ammeter of 8A, 10A, 9S and 16S all supports four line Y shapes and four thread triangles electricity to safeguard.Because the voltage vector Va in four line Y shapes and four thread triangle systems different with the displacement of Vc (turn to be respectively 120 ° and 90 ° for ABC), carry out for the phase vector of guaranteeing system is calculated effective measurement of angle lag behind start a reasonable time after, displacement between system measurement Va and the Vc voltage vector, and determine according to this displacement whether this ammeter is mounted in four line Y shapes or the four thread triangle systems.

Equally, for ammeter form 6S or 6A, whether the displacement of system measurement Va and Vc phase vector is in 120 ° allowed band (best ± 10 °), is mounted in during suitable four phase Y shapes electricity that it is supported safeguards to guarantee ammeter.For the 12S ammeter, whether the phase angle of system measurement Va and Vc phase vector is in the threshold value of 60 °, 120 ° of permission or 180 °, if then measure and be installed in three thread triangles, network or the single-phase electricity ammeter in safeguarding respectively.At last, for 5S, 5A and 26S form, systems inspection Va and Vc phase vector are to measure in each the permission threshold value that whether drops on that three thread triangles (60 °), four thread triangles (90 °) or four line Y shapes (120 °) safeguard in its phasing degree, if then write down corresponding electricity and safeguard type.

It should be noted that under 5S, 5A or 26S form, four line Y shape and network operations can not be distinguished by system, because the angle between Va and the Vc phase vector all is 120 ° for these two kinds of maintenances under ABC rotation.Yet owing to adopt the application of 5S also few at present in network, in one embodiment, system only supposes that one 120 ° Va/Vc angular displacement is four line Y shape electric system.It should be understood that if ammeter is actually to be used in the network operation, be installed at one's discretion in the four line Y-networks ammeter and safeguard automatically how sensing function is measured, and ammeter will correctly move.Yet, since there are 30 ° of phase shifts in the four line Y shapes between electric current (I) and the voltage (V), and electric current and voltage phase vector can not be offset mutually in the network operation, safeguard that 5S, the 5A of sensing function or the ammeter of 26S form are used in the network if comprise above-mentioned automatic electricity, then some diagnostic calculation (diagnose as described 1 and diagnosis 4) may untrue ground indication fault.

Should be understood that this system equally can be by checking that voltage phase vector and/or other information that automatic diagnosis obtained realize the electricity maintenance that other form ammeters are housed is detected automatically.

Be to be further noted that the indicated angular displacement of Figure 21 is for the ABC order.In carrying out electricity maintenance mensuration, system preferably also checks Va and the Vc value of angular displacement that ABC turns to.Should be understood that in CBA turned to, C phase voltage phase vector Vc should be 360 ° of positions that deduct Vc shown in Figure 21.

The process flow diagram of the automatic maintenance test function that adopts in Figure 22 and 23 expression one embodiment of the present of invention.Each ammeter powers up, or system diagnostics is when setting up again, and ammeter is checked maintenance function with executive system.This can be by safeguarding that type returns to an invalid value and starts.When starting or after the reconstruct (for example, power failure), system will discern this invalid value, and begin to carry out a kind of effective mensuration of safeguarding type automatically.

The diagnosis time-delay of a scheduled duration is set, for preferably getting about 8 seconds, so that ammeter is stable and five kinds of possible phase vectors will calculating are carried out measurement of angle with the ammeter of 60Hz operation.Therefore, between this time delay, safeguard that automatically sensing function does not operate, because Va and Vc phase vector value may be unreliable.After the diagnosis time-delay, safeguard that automatically sensing function starts finally in each sampling interval (is 1 second for 60z), until finding a kind of effective maintenance.Any diagnosis has started in system if effective maintenance is not found, and the inefficacy that then this mensuration is effectively safeguarded will be designated as diagnosis #1 fault.If diagnosis is not activated, then protocol failure is not safeguarded fault.Automatically safeguard in the system embodiment of sensing function using, can not appear on the display for the diagnosis #1 fault of an invalid maintenance, unless diagnosis #1 can roll or lock, as described herein.

As long as do not find effective maintenance, diagnosis just can not be examined.Effectively safeguard (being recorded in the type of safeguarding in the system) in case determine one, safeguard the sensing termination automatically, ammeter just begins between each sampling period deagnostic test to be made in those system diagnosticss that started, as following described.

Should be noted that in an example of the present invention, when the detection inefficacy is safeguarded in appearance, diagnose the operation of #1 inefficacy and normally diagnose the #l inefficacy slightly different.If in checking first, do not find immediately and safeguard type,, then start a diagnosis #l and lost efficacy as long as have a system diagnostics function operation at least in the system.As long as find that one is effectively safeguarded, diagnosis #1 fault is just removed immediately.Only in the time diagnosis #1 being rolled or lock, fault just can show on ammeter.As long as one of system diagnostics can start, this inefficacy always is recorded in the diagnosis #1 failure counter.All be not activated as system diagnostics, then this inefficacy just can not be recorded.This allows the user to select to turn off any warning.

It should be noted that in the implementation shown in Figure 22 and 23, the tolerance limit that system allows a voltage phase vector position (preferably ) so that by diagnosis.In the operation, very limited in view of the variation of voltage phase vector, generally in 1 ° or the 2 ° scopes in its balance resistive load position, this tolerance limit is proved to be enough at the scene.The user determines diagnosis

System preferably allows the user to enable between the ammeter installation period or stops using one or more system diagnosticss.If diagnose, system preferably also provides user-defined parameter, and is as described below.

In order to start or to close any one above-mentioned deagnostic test, the user must answer the following type prompting in every kind of deagnostic test programming software being supported by system.

" diagnosis #N forbids "

To each " diagnosis N " (wherein among the N representative diagnosis sequence number 1-4), when pressing the Return key, the user obtains a menu, preferably includes at following option:

Disable (forbidding)

Ignore (ignoring)

Lock (locking)

Scroll (rolling)

Disable selects to stop the execution of that diagnosis.

Ignore selects (if execution) to mean diagnosis will influence malfunction alarm (as described below), but can not show.

Lock selects (if execution) tracing trouble information to be locked on the ammeter display recording.

Scroll selects (if execution) will be after finding tracing trouble, during " off time " between each normal mode display items, and the tracing trouble information that generation will show.

Except that above prompting, also will point out the user that particular meter is installed the electricity of supporting and safeguard type (as 4-line Y shape) programming.

For diagnosis #2, also can point out the user to insert the tolerance that a numerical value (preferably corresponding to a percentage tolerances) designs all voltages, to respond following prompting:

Diagnosis #2 percentage tolerances: _ _ _ _ _ _

For diagnosis #3, preferably point out the user to design acceptable minimum current level, to respond following prompting:

Diagnosis #3 minimum current: _ _ _ _ _ _

Diagnosis #4 preferably also points out the user by inserting the phase angle tolerance that a numerical value (1-90 °) designs permission, to respond following prompting:

Diagnosis #4 phase angle tolerance: _ _ _ _ _ _

If selected Lock or Scroll, as long as detect tracing trouble, ammeter will show following message:

Fault diagnosis N (wherein N=diagnosis numbering)

Simultaneously, when detecting fault, the generation number of this failure counter just adds 1.But in a preferred embodiment, appearred just producing the systems response information and initial demonstration of tracing trouble as previously mentioned, in continuous three times are checked up to malfunction.Equally, fault does not exist in twice continuous review, and this fault just disappears from display.

In addition, during " off time " (resting) between each normal mode ammeter display items, show or be locked on the failure message, or by showing the failure message that rolls, the setting when this is decided by that system installs.Various other display packings consistent with the technology of the present invention all can adopt.The ammeter self-check

Preferably system 20 of the present invention is done suitable program design and carry out a series of ammeter self-checks periodically, if detect any fault, system will write down and a malfunction occur, show a failure code, and take other suitable actions according to fault type corresponding to the survey fault type.

System preferably carries out a series of programs of critical failure and non-critical fault being carried out periodic test.So-called critical failure is meant that the inefficacy of detection may be that record data are unreliable, may cause that maybe ammeter moves the fault of a unreliable class in the future.System 20 preferably carries out the ammeter self-check, and the inspection ammeter is deposited the internal RAM of module, deposits the ROM of module, deposits the EEPROM of module, deposits pseudo-RESET and front-end module internal RAM, ROM and the EEPROM of module.Whenever the back ammeter that has a power failure restarts or ammeter when reconfiguring, preferably these ammeter parts are checked one time.As detect RAM, ROM, front-end module processor fault or other critical failures, system 20 can show the predetermined failure code corresponding to the survey fault, display lock is fixed on this code, reinitialize up to ammeter, and termination all ammeter functions except that communication.

System 20 deposits module handler by detection and whether runs into a hardware RESET at the blackout procedures of not being scheduled to earlier and check the power down fault.This situation may be on supply lines transient process moment take place when touching (assert) RESET line.A kind of method of checking pseudo-RESET is that a special character is write among the register EEPROM as the final step that has a power failure and handle.If this special character does not occur when powering up, pseudo-RESET has then taken place once.20 of systems will show this power down failure code, and end all the ammeter functions except that communication.

System checks that with the same manner RAM, ROM, EEPROM and the processor of front-end module lost efficacy, as mentioned above.In the example that is made up by Fig. 3 ammeter, as finding any critical failure of front-end module, then front-end module will stop and the communicating by letter of register module.If communication disruption was above 5 minutes between front-end module and the register module, then be enough to assert one that detects in this class fault, just show a front-end processor failure of removal code, and assert and recover normal operation up to front-end module by 68HC11 RESET line.

The ammeter self-check of being carried out by system preferably also comprises a series of non-critical faults, and for example the register full scale is overflowed, system clock, service time (TOU), mass storage, backward power stream and A-battery malfunction.

For example, if peak K w register surpasses the register ull-scale value that presets, will report a register full scale overflow fault.If detect this situation, system demonstrates a register full scale overflow fault, when ammeter restarts or by predetermined programmer during with fault clearance, this fault promptly is eliminated.

As minute, the time, day or month data exceed preset range, then will report a clock failure.As producing clock failure, TOU and memory span are selected and will be under an embargo, and end the logging interval data and reset up to ammeter.

If an inner TOU parameter becomes unreliable or contains its predetermined allowed band value in addition, will report a TOU fault.As the TOU fault takes place, will show corresponding failure code and forbid that TOU selects.

If the internal mass memory storage parameter becomes unreliable or exceeds its predetermined allowed band, will report a mass storage fault.If the mass storage fault then shows corresponding failure code and forbids the mass storage selection.

If front-end module in the opposite direction detects the equivalent information of a complete and continuous dial plate rotation, will report a backward power stream fault.No matter whether energy stabilization, always report this fault.

If confirming has the LOBAT signal on power combinational circuit, then will report an A-battery fault when level is checked.If detect the A-battery fault, will show corresponding failure code, the same with clock failure, will end all TOU and mass storage and select.If before any outage, change battery, then rise to predetermined threshold when above when cell voltage, the A-battery fault will be eliminated.Yet if outage back cell voltage is lower than threshold value, ammeter must be set up again and be removed this fault.

The full scale of checking register finally that system is preferably in each requesting interval is overflowed, and be preferably in when powering up, 2300 hours and when any type of electrical table reconstruct, clock, TOU and mass storage fault are checked.Backward power stream fault preferably once by system's per second inspection, and when energising and each every once to the A-battery trouble shooting.

In the preferred embodiment of system 20, system allows the user to select to carry out which ammeter self-check function.In preferred embodiment, if detect any selected non-critical fault, during the off-time between the normal display items, system can show a predetermined failure code corresponding to tested fault.On the other hand, in case detect any this fault, system can allow the user that systems programming is locked in demonstration on the failure code of arbitrary non-critical fault.In this case, start a switch by the user and will make ammeter pass through normal display menu rolling once, be locked in non-critical fault then and show.

Should be noted that in preferred embodiment, can not forbid the critical failure inspection.If the non-critical fault inspection is not selected, it just can not be shown and indicate.

Those those of skill in the art understand can adopt various display packings.For example, can demonstration be locked on the failure code corresponding to any non-critical fault that records, start up to magnetic switch to systems programming.In case magnetic switch starts, system then can pass through its normal display scrolling, is locked in then in the demonstration of non-critical fault code.In addition, can make systems programming and continue to roll, show any or all of non-critical fault code periodically by predetermined demonstration inventory.

Other ammeter parts can adopt the failure code of conventional method and setting to do same periodically inspection, when being fit to the unreliable running of possible data interruption of call user's attention or ammeter, can show these codes.The tool box pattern

The diagnostic tool case is one group of fixing display items of selecting of form shown in Figure 14 preferably.In preferred embodiment, the tool box demonstration is to come access by a magnet spring switch that is in 12 o ' clock positions on the dial plate, and by magnet was started near snap switch at least in 5 seconds.Can place magnet the top of ammeter to realize by the user.

When access, each display items in tool box press respectively Figure 14 and shown in order show.In case ammeter is in the tool box display mode, all tool box display items will roll once at least.After magnet is removed, ammeter will be accomplished to the rolling at the bottom of the tool box shows inventory, return to the normal mode operation then.During ammeter was in tool box pattern whole, the TEST alarm can flash twice by per second.

All #DIAG Error counters are preferably by an external device (ED) zero clearing, for example a handheld personal computer or pass through normal communication.In preferred embodiment, the maximal value of each counter is 255.

When being in the tool box pattern, ammeter work is carried out as usual, even guarantee that so just magnet rests on longer a period of time of ammeter top, the ammeter operation is still unaffected.During ammeter was in tool box pattern whole, along with the variation of its value, system revised the tool box parameter of demonstration continuously.

Under the tool box pattern, Watt Disk Emulator (watt dish simulator) rotates in this that phase power circuit direction that shows its information constantly along proper with the speed of 1.33 seconds one circles.For example, when A phase voltage, electric current, voltage phase angle and electric current phase angle were showing, Watt Disk Emulator pressed A phase power circuit direction per second and rotates once.In case show (if existence) when B is worth mutually that if B phase power circuit is mutually opposite with A, Watt Disk Emulator turns to counter-rotating.When four rotation failure counters all have demonstration, Watt Disk Emulator is turned off.

Because the continuous current potential indication of customer requirements, triphasic potential is indicated (preferably with V _A, V _BAnd V _CExpression) all appears on the display screen.As long as corresponding voltage is in more than the predetermined threshold value, these indications are " ON ".75% of the minimum voltage value that this threshold value best definition is the ammeter nominal operation.If any voltage drops to below the threshold value, its indicator preferably flashes with the speed of per second 2 times,

When having an above fault simultaneously,, only show the information relevant with one of them fault according to predetermined priority ranking.In the preferred embodiment of native system, set up following priority ranking:

1. ammeter self-check fault has precedence over system and tracing trouble is installed.

2. owing to a system is at a time only arranged and tracing trouble is installed and can show, the fault of high precedence will be a fault that adopts the predetermined priority order inventory to show.

If have two or more systems and tracing trouble is installed, the fault of high precedence will be that fault that is shown, and be that triggers the fault that output contact is closed.If this fault is repaired, will shows the highest precedence fault of the next one that still exists, and will trigger output contact once more and close.Therefore, as long as there are one or more tracing troubles to be triggered, close (malfunction warning) with regard to assert output contact all the time.

As mentioned above and shown in Figure 14, the tool box shows the instantaneous value that preferably also shows every phase current and voltage.And with respect to the phase place of A phase voltage.According to these information, the user can constitute the phasor diagram that helps define correct installation and operation ammeter.The tracing trouble number of the long-pending meter of each diagnosis since last subsystem clear operation has also been represented in this demonstration.

Figure 14 and 15 provide respectively phasor diagram that three-phase kilowatt-hour meter installs and tool box show between the example of required relation.Utilize the phase current, voltage and the phase angle information that provide in the tool box demonstration, the user should be able to constitute polar plot as shown in figure 15.This will allow the user to obtain the snapshot of POWER SYSTEM STATE, and be used for differentiating any feature and fault.As previously mentioned, the tool box also will provide the state of four kinds of diagnosis counters, and it will provide more detailed system status information for the user.Phase angle calculates

In a preferred embodiment, the phase angle information that shows desired phase current and voltage with the tool box that is adopted among system diagnostics #1 and the #4 is determined from every add up electric current and current value and accumulative total product Q and Y (definition below) mutually.The A phase voltage preferably is used as the reference (or benchmark phase vector) of other angles.Therefore, A phase voltage angle in demonstration with 0.0 ° of appearance.For (I _A, I _B, I _C, V _B, V _C) these five other angle values will be reported with respect to the A phase voltage value, and the general always provides with respect to the reference value of a hysteresis.1. V _AWith I _ABetween phase angle

If known power (Power) and applied power (Apparent Power) then can be released power factor.

Concern as follows:

Applied power=I _RMSV _RMS

Power factor=power/applied power=power/I _RMSV _RMSPhase angle between voltage and electric current (θ) then can be calculated as follows:

θ=arc cos (power factor)

Device of the present invention also can determine that electric current is leading or lags behind voltage by the symbol of checking reactive power.If reactive power is for just, then electric current lags behind voltage, and if reactive power for negative, then electric current is led over voltage.

In the present embodiment, per 60 line periods calculate once power, RMS voltage and the RMS electric current of the every phase of ammeter.This finishes by 481 voltages of work and current sample in 60 line periods.Elder generation does multiplying each other of necessity and adds up, and then these values is asked average to provide power, RMS voltage and the RMS electric current to 60 given line periods.Calculate the power factor of every phase more finally in per 60 cycles with this tittle.

Must induct except that between electric current and voltage measurement 90 ° of phase shifts, reactive power can be calculated by the method identical with power.2, the derivation of general phase angle meter algorithm

Prove as following, can will calculate V _ATo I _AThe method of phase angle promote calculate any with reference to phase vector (such as V _A) with any other phase vectors (such as V _B, I _B, V _C, or I _C).

Referring now to Figure 16, consider identical as lower frequency, amplitude is different and two sine waves of phase shift are arranged each other:

at)＝Acos(ωt)

b(t)＝Bcos(ωt-9)

The cosine phase angle is expressed as (ω t-θ), its implicit hypothesis is that to represent b (t) be a hysteresis phase shift of reference with a (t) to θ.Location tables separately is shown in the time, and to go up b (t) be at a (t) before or reaching its maximal value thereafter.If b (t) reaches its maximal value afterwards at a (t), then claim it to lag behind a (t).If b (t) reaches its maximal value before at a (t), then claim it to lead over a (t).

For the purpose of separating phase angle theta, the mean value of these two sinusoidal wave products will be calculated.This mean value will be with the Q mark.The equation of averaging is as follows: $Q=\frac{1}{T}\underset{0}{\overset{T}{\∫}}A\cos \left(\mathrm{\ωt}\right)B\cos (\mathrm{\ωt}-\mathrm{\θ})\mathrm{dt}$ A and B represent the amplitude of sinusoidal wave a (t) and b (t) respectively in the formula.A sinusoidal wave amplitude X _MAXWith its RMS (root mean square) value X _RMSRelevant, be expressed from the next: $X_{\mathrm{MAX}}=\sqrt{2}{X}_{\mathrm{RMS}}$ Therefore, $A=\sqrt{2}{A}_{\mathrm{RMS}},B=\sqrt{2}{B}_{\mathrm{RMS}}$ With these equations that concerns substitution Q, then obtain: $Q=A_{\mathrm{RMS}}{B}_{\mathrm{RMS}}\cos \mathrm{\θ}$ Or $\cos \mathrm{\θ}=\frac{Q}{A_{\mathrm{RMS}}{B}_{\mathrm{RMS}}}$ Obtain at last: $\mathrm{\θ}=\mathrm{arc}\cos \left(\frac{Q}{A_{\mathrm{RMS}}{B}_{\mathrm{RMS}}}\right)$

Therefore, the RMS value as the mean value and the two single ripples of known two sinusoidal wave products then can calculate two phase angles between the ripple.This information is only arranged, and we can't determine that b (t) lags behind or leading a (t).Yet,, just can determine that this angle is the angle of lead or drag angle if known the symbol at θ angle.

In order to determine the symbol of this angle, consider the mean value of two sinusoidal wave products, establish the phase shift that a (t) has 90 ° or pi/2 radian.The phase shift modification expression of a (t) is as follows: $\hat{a}\left(t\right)=A\cos (\mathrm{\&omega;t}-\frac{\mathrm{\&pi;}}{2})$ A (t) will the amount of being called Y with the mean value of b (t) product.Equation is as follows: $Y=\frac{1}{\mathrm{<figure-callout\; id="0"\; label="T"\; filenames="A96191021.600511.png"\; state="\{\{state\}\}">T</figure-callout>}0}\underset{0}{\overset{T}{\&Integral;}}A\cos (\mathrm{\&omega;t}-\frac{\mathrm{\&pi;}}{2})B\cos (\mathrm{\&omega;t}-\mathrm{\&theta;})$ Separate this integration and promptly provide following relation: $Y=\frac{\mathrm{<figure-callout\; id="2"\; label="AB"\; filenames="A96191021.600511.png"\; state="\{\{state\}\}">AB</figure-callout>}}{2}\sin \left(\mathrm{\&theta;}\right)$

Therefore, if the mean value of known two sinusoidal wave products (Q), the mean value (Q) of these sinusoidal wave products that known reference ripple time-delay phase shift is 90 °, and the RMS value of known each ripple, then can calculate phase angle, and determine that non-reference wave is hysteresis or leads over reference wave.Can be used to determine that two equations of phase angle size are as follows: $\mathrm{\&theta;}=\arccos \left(\frac{Q}{A_{\mathrm{RMS}}{B}_{\mathrm{RMS}}}\right)$ $\mathrm{\&theta;}=\arcsin \left(\frac{Y}{A_{\mathrm{RMS}}{B}_{\mathrm{RMS}}}\right)$ Investigate the symbol of arc cosine (arccosine) and inverse sine (arcsine) function argument, can determine that this angle is the drag angle or the angle of lead.Since positive angle corresponding to drag angle, then descends relation of plane to be used for determining that this angle is that the drag angle or the angle of lead are exactly right:

Arc cosine argument (+), inverse sine argument (+)

-lag behind 0 ° to 90 °;

Arc cosine argument (-), inverse sine argument (+)

-lag behind 90 ° to 180 °;

Arc cosine argument (-), inverse sine argument (-)

-leading 90 ° to 180 °;

Arc cosine argument (+), inverse sine argument (-)

-leading 0 ° to 90 °.Therefore, Q, Y and the RMS value of a (t) and b (t) if can be tried to achieve, the phase angle between these sine waves can be determined.

The above-mentioned technology of asking phase angle will be applicable to that any voltage or electric current are right.For example, for determining V _BWith V _ABetween phase angle, the mean value (Q that two amounts must calculating are two ripple products _VAB), and V _AMean value (the Y of these two ripple products that phase shift is 90 ° _VAB).

As previously mentioned, incorporate into ammeter in system's 20 preferred embodiments in per 60 line periods to V _BAnd V _ASample 481 times.Each of 481 samplings is calculated V _AAnd V _BProduct, and in sampling interval, add up, then can calculate the mean value (Q of these two ripple products finally in sampling interval _VAB).To Q _VABEquation as follows: $Q_{\mathrm{VAB}}=C\frac{\underset{n=1}{\overset{481}{\mathrm{\&Sigma;}}}{V}_{A\left(n\right)}\&times;V_{B\left(n\right)}}{481}$ C is used for compensating phase voltage to drop to a computing scale factor can measuring level in the formula.

Y _VABAvailable similar method is tried to achieve from following formula: $Y_{\mathrm{VAB}}=C\frac{\underset{n=1}{\overset{481}{\mathrm{\&Sigma;}}}{V}_{A(n-2)}\&times;V_{B\left(n\right)}}{481}$ In the formula to calculating Y _VABC with calculate Q _VABC be the same, V _{A (n-2)}Be prior to sampling V _AnThe voltage V of double sampling _A

The design of sampling will make twice continuous sampling of a signal be separated by 44.91 °.Therefore, if before the double sampling to voltage sample, this will produce and be close to 89.82 ° of phase shifts of 90 °.

Should be noted in the discussion above that and replace using V _APhase shift sampling, also other can be measured phase shift and calculate phase angle for 90 °.This will obtain onesize Y _VA _BValue.Yet, owing to 180 ° of phase angle shifts, thereby with reindexing information.Press with this side, then have following syntactics between arc cosine and the arcsin function argument:

Arc cosine argument (+), inverse sine argument (-)

-drag angle is between 0 ° to 90 °;

Arc cosine argument (-), inverse sine argument (-)

Between 90 ° to the 180 ° of-drag angle;

Arc cosine argument (-), inverse sine argument (+)

Between 90 ° to the 180 ° of-angles of lead;

Arc cosine argument (+), inverse sine argument (+)

Between 0 ° to the 90 ° of-angles of lead.

If each sampling interval computational tool case is shown the new value of necessary phase angle, then must calculate above-mentioned ten product terms and the item that adds up to each sampling interval.Owing to the too much use processor time and with whole ten in each sampling interval needed RAM that add up, preferably every section sampling interval is only considered a pair of of these.This has just limited the use of processing time and RAM, thereby per five sampling interval just can obtain the new angle values to the tool box demonstration.

In a preferred embodiment, calculate product term and adding up in the following order:

1. first sampling time section-phase angle I _AV _A* I _AAnd V _{A (90 °)}* I _A

2. second sampling time section-phase angle I _BV _A* I _BAnd V _{A (90 °)}* I _B

3. the 3rd sampling time section-phase angle I _CV _A* I _CAnd V _{A (90 °)}* I _C

4. the 4th sampling time section-phase angle V _BV _A* V _BAnd V _{A (90 °)}* V _BAnd

5. the 5th sampling time section-phase angle V _CV _A* V _CAnd V _{A (90 °)}* V _CAfter the 5th sampling interval, order is restarted, will be to phase angle I _AEssential Q value and Y value add up.Will be in each sampling interval to V _ASampling store.This just requires will store V at interval at each _ATwo added values, i.e. two previous V _AValue.

In the present embodiment, these functions are carried out with the 68HC11 assembler code.Multiplying each other and adding up of these product terms appears in the front-end sampling interruption routine.Magnitude of voltage is 8 place values, and current value is 12 place values.Since V _AAlways twist in any one product, this just means that some product will be 8 * 8, and some will be 8 * 12.Owing to wish to make all multiplication, expand 8 place values to 12 place values, so that only 8 * 12 multiplication be used in a preferred embodiment with identical algorithm.

With V _BAnd V _C8 magnitudes of voltage expand 12 place values to through symbol and make and all of product term to be multiplied each other and add up and adopt two kinds of algorithms to handle for trying to achieve phase angle, a kind of is to the adding up of the product term of Y value, the adding up of a kind of product term of the Q of being value.Magnitude of voltage V _BAnd V _CSign extended in each sampling interval, carrying out.This tailor-made special inspection of just differing is differentiated the sampling interval of this tittle of needs, because they can obtain in each sampling interval.

Whole 12 place values of electric current and voltage preferably are stored in 16 bit registers of storer, because storer is by the byte boundary subregion.

The front-end sampling program must have a kind of method to discern which product term will to calculate in each sampling interval.Preferably adopt counter identifier to do index and be the correct value of the necessary multiplying access of adding up of Q value and Y value.

For two product terms are added up, two totalizers are set on the memory map side.The size of each totalizer is the same, because the both does 8 * 12 multiplication.The aggregate-value of maximum possible is as follows:

Maximum 8 place values=128

Maximum 12 place values=2048

Maximum accumulation result=481,*12,8*2,048,=07 84 00 00 (sexadecimal) therefore, each totalizer 4 byte long is so that the result under the worst case that adds up.Therefore, the side totalizer of establishing two 4 bytes comes every pair of product term of each sampling interval of accumulative total.

In each sampling interval finally, the result in two 4 byte totalizers is stored in two 4 bytes keeps the district, calculate the necessary background program processing of phase angle between sampling period next time to wait for to finishing.

In case the product term through adding up then carry out on the backstage between next sampling period for determining the necessary subsequent calculations of phase angle, and will add up to following a pair of product term in the foreground to after being sent to the maintenance register finally a sampling interval.These background programs must have the ability also to determine they will add up product term to calculating to which.A kind of discrete counter identifier is used for this background program, and it operates in the mode identical with the counter identifier that front-end sampling is interrupted.Yet,, thereby might adopt same counter since this identifier is a counting after the front-end module sampling interrupt routine counter identifier all the time.

The ammeter 34 that has disposed system 20 of the present invention shown in Fig. 2,3,17A-B and the 18A-B especially is a kind of solid-state single function Kw/Kwh ammeters that adopt the digital sample technology, except the diagnostic message that is produced by system 20 of the present invention is provided, also provide general Kw/Kwh demand, service time and other conventional charging informations in real time.Ammeter 34 preferably adopts the software programming that runs on IBM-compatible personal computer under MS-DOS operation system.This software comprises that the prompting user provides the logical program of ammeter configuration parameter, preferably include and be provided as the used user of diagnosis that system of the present invention 20 supports-determine the installation suggestion of parameter, make handheld personal computer can inject the communication port on the ammeter and when mounted ammeter is programmed.

The front-end module 44 of the ammeter 34 that Figure 17 A-B explanation is preferentially made up system 20 of the present invention.Front-end module 44 preferably includes a Notorola MC68HC11KA4 microprocessor 140 with single chip mode work, integrated 8 A/D converters 142 (as the voltage changer 26 in the system 20 of the present invention) can be wiped programmable read-only memory (EEPROM) and 768 byte random-access memory (ram)s with 144 overall 24K byte ROM (read-only memory) (ROM), the 640 byte electricity that indicate.ROM and EEPROM comprise the diagnostic logic device, and RAM is as storer of the present invention.12 A/D converters in an outside shown in 146 are as the power pack 28 of system 20 of the present invention.

A kind of selection that additional fault status alert function can be used as on the front-end module 44 is carried out.This function is led to external communication device with a data line (for example), and malfunction one is measured, and just it can be started.System 20 of the present invention can utilize this selection function to start and keep accounts the existence of any malfunction by system of the present invention 20 performed diagnosis.

An option board 146 can be injected front-end module 44 and provide various signals for the external world.For example, malfunction can be reported to the police and be set to the solid-state or mercury-infiltration relay of low current and indicate when be measured to one or more tracing troubles.Other subsidiary functions such as automatic ammeter reading or record keeping in real time all can realize on the option board or on the option board of the similar formation of using with front-end module.

Referring now to Figure 18 A-B, the register module 48 of the ammeter of preferential configuration system 20 of the present invention comprises a NECuPD75316GF chip microprocessor 148,16K byte ROM (150 expression), 512 * 4 bit RAM (152 expression), and 96 sections LCD display drivers 154, be suitable for driving as shown in Figure 3 and be used for the LCD display 156 of ad hoc type display 33 of the preferred embodiment of ammeter 34.

The four line locking serial data lines that 158 places that serial data will be by Figure 17 A-B and 160 places of Figure 18 A-B represent respectively transmit between front-end module 44 and register module 48.All performed diagnostic states by system of the present invention 20 will be monitored and upgrade to front-end module, and by above-mentioned serial communication line periodically (preferably per second once) these states are kept accounts to the data that register module 48 shows and storage is easily lost when the outage.In addition, for showing desired any instantaneous flow, tool box of the present invention must be delivered to register module by front-end module.Front-end module 44 also passes to register module 48 with various other conventional ammeter information, for example, and to the energy usage (is unit with Kwh) of 60 line period records of firm past, and direction of energy flow (send or receive), current demand and interval ending message.

Can generally comprise cycle ammeter buffer status information from the information that register module 48 leads to front-end module 44.

Referring again to Figure 17 A-B, front-end module 44 can make whenever-and the wattage of phase voltage, electric current and a sampling interval measured.As previously mentioned, preferably per 60 line periods of front-end module are done 481 samplings, and when line frequency was 60Hz, this was equivalent to 481Hz, and when line frequency was 50Hz, this was equivalent to 401Hz.This sample frequency will recomputate according to per 60 cycles of line frequency of measuring.As previously mentioned, when system of the present invention incorporated in the type ammeter shown in Figure 3, its diagnostic function (comprise instantaneous every-mensuration of phase current, voltage, wattage and phase angle) was preferably carried out by front-end module 44.

Refer again to Fig. 3 and 18A-B, register module 48 is preferably carried out the function that drives LCD display 33 in the ammeter 34.As previously mentioned, tool box of the present invention shows that can start an alternation display switch (not shown) by the predetermined cycle realizes.During startup, trigger the tool box display mode, then show rolling entire tool case display menu, aforementioned as this paper.During the tool box showed, " TEST " icon preferably flashed continuously, and watt dish simulator (being expressed as five rectangle icons of display 33 bottoms) will roll with approximately per speed that circled in 1.33 seconds.The direction of watt dish simulator will be same as the power circuit direction that is shown phase (during reception from left to right, during transmission from right to left).When the alternation display switch is not restarted when arriving the demonstration end, ammeter will keep the tool box display mode.Should be noted in the discussion above that as previously mentioned when the tool box DISPLAY ORDER is effective, ammeter will continue to carry out the ammeter running of all normal modes.

When not starting the alternation display switch, ammeter display 33 is pressed normal displaying mode to ammeter 34 runnings.

Also can finish with being connected of optical port 162 to ammeter or from the communication of ammeter by front-end module 44 warps.

Therefore, whole ammeter system diagnostics of the present invention comprises except reminding the field staff to note the fault of any discovery, also do not interrupting providing the ammeter internal part ability that continuous self test is looked under the ammeter working condition, this system also provides frequent system diagnostics inspection and shows the ability of diagnostic result, so that in the ammeter installation process or after installing relevant diagnostic data is offered system personnel.

This system provides and allows the user that systems programming is selected and determine to be fit to by ammeter the special maintenance function supported and the dirigibility of parameter to be installed.

At last, tool box of the present invention display performance also under the situation of not interrupting conventional maintenance and ammeter work the permission cycle show the important information of the maintenance characteristics that relevant ammeter internal operations and ammeter are supported.

Though to realizing that best way of the present invention made detailed description, the those of skill in the art that invention field is relevant can make by the determined enforcement of following claim various design of the present invention and example therewith.

Claims (12)

1. an electronic electricity meter detection electric system diagnostic device comprises:

A microprocessor;

The storer that rationally is connected with microprocessor;

Be used for carrying out automatically periodically pre-selected test that ammeter detects and the logical circuit that writes down measured any fault;

Be used for carrying out automatically periodically the logical circuit that any result who exceeds predetermined threshold was tested and write down in a series of pre-selected system diagnostics;

Be used for showing expression because of in predetermined period the ammeter of the doing display device of testing the failure message of one or more faults of finding, and

Be used for showing the display device of expression because of any Fault Diagnosis information of in predetermined period, doing the ammeter diagnostic test and finding.

2. the system of claim 1 also comprises and is used for automatically measuring the logical circuit that the electricity that ammeter is housed is safeguarded type.

3. the system of claim 2 wherein is used for measuring automatically the electricity that ammeter is housed and safeguards this mensuration of execution in the initialization procedure of logical circuit when ammeter is installed of type.

4. the system of claim 3 wherein is used for measuring automatically the electricity that ammeter is housed and safeguards that the logical circuit of type carries out this mensuration when ammeter reconfigures.

5. the system of claim 2 wherein is used for measuring the electricity that ammeter is housed and safeguards that the logical circuit of type carries out this mensuration automatically and periodically in the ammeter normal work period.

6. an ammeter electric system diagnostic device comprises:

A microprocessor;

The storer that rationally is connected with microprocessor;

Be used for automatically measuring the logical circuit of the electric system type that ammeter is housed.

7. the system of claim 6 also comprises the logical circuit that is used for determining the power system voltage information record thus.

8. the system of claim 6, the logical circuit that wherein is used for measuring power system voltage information comprises in order to measure the logical circuit of at least one voltage phase vector with respect to the phase angle of a selected reference voltage phase vector, and wherein be used for measuring electricity and safeguard that the logical circuit of type comprises and be used at least one phase vector with respect to the voltage phase angle of a selected reference phase vector and a different set ofly may safeguard that the pre-selected voltage phase vector angle of type compares by electricity, if and had electricity to safeguard type, would determine that according to voltage phase vector angle electricity safeguards the logical circuit of type.

9. the system of claim 8 wherein is used for measuring electricity and safeguards that the logical circuit of type is according to C phase voltage vector V _C, A phase voltage vector V _AAnd the predetermined form factor of ammeter carries out this mensuration.

10. the system of claim 9 wherein is used for measuring at least one phase vector and comprises with respect to the logical circuit of the phase angle of a selected reference phase vector and be used for storage corresponding to benchmark phase vector X _BThe accumulating values of the instantaneous voltage that records, storage are corresponding to another selected reference phase vector X _NThe accumulating values of the instantaneous voltage that records, in a predetermined period, measure and be labeled as X respectively _{B (RMS)}And X _{N (RMS)}X _BAnd X _NThe RMS value, measure X _{B (RMS)}And X _{N (RMS)}Product P, measure corresponding to X _BAnd X _NThe mean value Q of two sinusoidal wave products, and measure and be labeled as X ^{B (90 °)}Corresponding to X _BThe logical circuit of the mean value Y of two sinusoidal wave products of phase shift modification.

11. the system of claim 10, logical circuit wherein also comprises and is used for measuring the phase angle theta size of a phase vector with respect to a selected reference phase vector, and size equals arc sin (Q/P), logical circuit.

12. the system of claim 11, benchmark phase vector X wherein _BBe A phase voltage phase vector, its another phase vector X _NIt is C phase voltage phase vector.

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