DE102007006564A1 - Line safety switch or circuit-breaker comprise input terminal and output terminal, which are connected by current path, where device measures phase of alternating current - Google Patents

Abstract

The line safety switch or circuit-breaker (10) comprises an input terminal (12) and an output terminal (14), which are connected by a current path. A device (26) measures a phase of an alternating current between one point in current path and one reference point. The electronic evaluation device (28) is arranged for actuating an actuator element (22) on a contact point (16).

Description

The The invention relates to a circuit breaker or circuit breaker according to the preamble of claim 1.

Of the Switch thus includes an input terminal and an output terminal. These are connected to each other via a current path. The current path is at a contact point by the action of an actuator element interruptible. In or on the current path are means for measuring a a property of a current flowing through the current path physical size, and means to measure the physical size are using electronic Coupled evaluation, which drive the actuator element.

A circuit breaker of the type mentioned results due to a Anwendungsgebietsinweises in the DE 41 11 831 A1 relating to a method for triggering an electrical switch and a device for carrying out the method.

the generic switch is the characteristic of own, that the actuator element is controlled electronically, unlike with numerous circuit breakers or circuit breakers of the Prior art, in which such an actuator element is part of a electromechanical chain of action is. The electronic control allows an adaptation of the switch to its actual use: in particular in cascade circuits there are upstream switches and downstream Switch, with the downstream switch the electrical consumers are closer. It should then be the principle of so-called selectivity apply, namely at a short circuit of the short circuit switch nearest the power interrupt. at Use of the electronic evaluation means as in the generic Switches can, for example, different threshold criteria depending on the position of the switch sitting in the cascade circuit.

With the principle of selectivity is accompanied by the requirement that the switches should have the capability, if possible quickly interrupt the flow of electricity. This ability is particularly needed when the switches downstream are so that the upstream switch does not have a short circuit current has to pass too long, but still enough Time is that the upstream switch a possible Switching the downstream switch waits or even itself can shut down in order to realize the protection function.

It Object of the invention, a circuit breaker or circuit breaker of the type mentioned in such a way that a particular fast shutdown is possible.

The Task is performed by a circuit breaker or circuit breaker solved with the features according to claim 1.

According to the invention the switch thus means for measuring the phase of a between a Point in the rung and a reference point (with reference potential) applied AC voltage, and these funds are also with coupled to the electronic evaluation means. The electronic Evaluation means are then designed to act on the actuator element effect on the contact point on the basis of such criteria, where the measured phase is taken into account.

The Invention is based on the recognition that during the formation phase a short-circuit current, the current increase in known network conditions and known phase position has a predictable course, and therefore the phase must be easily measured.

The Formation phase of a short circuit includes a period of time typically much smaller than a period of line frequency.

at known network conditions has a short-circuit current depending from the phase angle of the occurrence of the short circuit a fixed course. With the set values and the measured voltage values and current values determines the electronics z. B. the current slew rate dI / dt at the phase angle determined from the voltage values and can determine very quickly whether it is short-circuit (look-ahead functionality). This is already predictable much earlier, before in conventional circuit breakers the magnet system active becomes. If necessary, then according to the given criteria the trigger. A downstream switch becomes clear have to trigger earlier than an upstream one. In addition, an upstream switch detects due to the constantly measured current profile, in particular the Current slew rate, whether a downstream switch alone can switch off.

Thus, it is a preferred embodiment that the means for measuring a physical quantity measures the current strength of the current flowing through the current path, that the electronic evaluation means calculate the time derivative of the current strength, and that at least one predetermined phase, the behavior of the time derivative of the current was determined empirically and the actual behavior with this empiri behavior is compared.

At the this embodiment is simplest to realize thereby that each phase is assigned a threshold value of the time derivative of the amperage becomes, possibly a limit of this time derivation at the time of exceeding another threshold by the current itself. The pairs of phases and limits then define a curve in a two-dimensional surface, wherein the curve is a region in which the actuator element is not for Acting on the contact point is prompted by an area delimits, in which the actuator causes the switching off of the switch. Of course, other sizes can be derived from the measured current. It offers for example, a measure of that of the Electricity calculated energy and in this also a Threshold criterion to use. Instead of simple threshold criteria can also do complicated evaluations of the graphs of the measured or determined quantities depending on take place from the time. Instead of limits assigned to the phases can also be a mathematical function, the corresponding Limits calculated.

The Invention has the advantage because of the fast shutdown that the short-circuit current does not reach the usual current level can develop. Since the triggering at downstream switches occurs very early in the formation of the short circuit, not enough electrical energy is flowing for the actuator, because the current value is still small.

While particular advantages in particular result from the fact that the turn-off at a short-circuit current is changed, the electronic evaluation means and the actuator element also for shutdown in case of overload can be used. This is preferred provided that in the just mentioned preferred embodiment of the invention in addition to the determination of the behavior Short circuit to every predetermined phase the behavior of the temporal Derivation of the current at overcurrent empirically is determined and the actual behavior with this Behavior is compared. Again, in addition to threshold criteria again Evaluations of the graphs of the physical quantities over the time is up. Alternatively or additionally, in case of overload the time integral over the amperage square considered in the electrical evaluation unit. A trigger occurs when the time-current characteristic specified by nominal current and standard is exceeded becomes.

Around the actuator despite the early shutdown with sufficient To supply energy, the actuator element is preferably an energy store associated, which in particular short-term energy for perform the action of the actuator element on the contact point can.

at In a particularly preferred embodiment, the electronic Evaluation means programmable, so that the circuit breaker or Circuit breaker to a specific network to which it is connected will, can be adjusted. For this an interface is provided, via the data from the outside can be fed to the electronic evaluation means are. In particular, such parameterization data should be that the specify the criteria specified, eg Which is the typical behavior Define the time derivative of the current as a curve.

following preferred embodiments of the invention below Referring to the drawings, in which:

1 schematically the structure of a circuit breaker or circuit breaker in a first embodiment of the invention, and

2 schematically illustrates the construction of a circuit breaker or circuit breaker in a second embodiment of the invention.

1 shows you as a whole 10 designated circuit breaker or circuit breaker having an input terminal 12 and an output terminal 14 includes. Between these two connections 12 and 14 electricity can flow. The current path is at a contact point 16 interruptible. The contact point 16 includes a stationary contact element 18 and a movable contact element 20 , In the closed position, the movable contact element touches 20 the stationary contact element 18 , A trigger 22 can act as actuator element, the movable contact element 20 from the stationary contact element 18 separate. The tripping should occur in the case of a short-circuit current or an overcurrent in the current path. To detect whether a short circuit has occurred, the following arrangement is used: In the rung are means 24 arranged to measure the current. medium 26 for measuring a voltage are arranged between the current path (phase conductor L) and a reference potential (neutral N). The means 24 and 26 transmit the measured values in the form of electronic signals to an electronic evaluation unit 28 , From the measured current strength directs the electronic evaluation unit 28 the time derivative of the current, the time integral over the square of the current and the integral of the current over time, from. From the measured voltage whose phase Psi is derived. The electronic evaluation device 28 preferably uses all of these quantities to detect whether the situation exists that the switch should turn off. In particular, based on the time derivative of the current and the phase, the occurrence of a short circuit can be detected at an early stage, namely during the development phase of the short-circuit current. The time integral over the square of the current is a measure of the energy that can be an additional criterion for deciding whether to trigger. Also the time integral over the current strength can be consulted. The electronic evaluation unit 28 is right with the trigger 22 coupled and causes it in the event of a short circuit early the contact point 16 interrupts.

In a conventional manner, a bimetallic element is used 30 for detecting an overcurrent. The bimetal element 30 is with the electronic evaluation unit 28 coupled, which is capable of bending the bimetallic element 30 detect by appropriate electrical signals and even with an overcurrent to the trigger 22 acts, so that this the contact point 16 interrupts. The bimetal element 30 Alternatively, it can also be applied directly to the trigger 22 act.

In the embodiment according to 2 is a circuit breaker or circuit breaker 10 built in his short-circuit release system the same as the switch 10 out 1 , Unlike the switch 10 out 1 includes the switch 10 ' but no bimetallic element 30 , Rather, the detection of an overcurrent occurs at the switch 10 ' also electronically. These are means 32 for measuring the current in the current path between the input terminal 12 and the output terminal 14 provided, which have a measuring range, which in particular allows the detection of an overcurrent. The means 32 are with the electronic evaluation unit 28 coupled, and this can be based on predetermined criteria (typical curves, exceeding of limits) recognize whether they trigger 22 must drive accordingly, so that the switch 10 ' is switched off.

The means 24 for measuring the current to detect a short circuit and the means 32 for measuring the current intensity for detecting an overcurrent can also be combined in a single ammeter or current measuring sensor, but then at the same time must have a correspondingly large measuring range and the corresponding measurement accuracy.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 4111831 A1 [0003]

Claims (5)

Circuit breaker or circuit breaker ( 10 . 10 ' ) with an input terminal ( 12 ) and an output terminal ( 14 ), which are connected to each other via a current path, wherein: - the current path at a contact point ( 16 ) by the action of an actuator element ( 22 ) is interruptible, - in or at the current path means ( 24 . 32 ) are arranged to measure a physical quantity representing a property of a current flowing through the current path, - the means ( 24 . 32 ) for measuring the physical quantity with electronic evaluation means ( 28 ) are coupled to the actuator element ( 22 ), characterized in that the circuit breaker or circuit breaker ( 10 . 10 ' ) Medium ( 26 ) for measuring the phase of an alternating voltage applied between a point in the current path and a reference point, which is likewise connected to the electronic evaluation means ( 28 ), and that the electronic evaluation means ( 28 ) are designed to prevent an action of the actuator element ( 22 ) to the contact point ( 16 ) on the basis of criteria that take into account the measured phase. Circuit breaker or circuit breaker ( 10 . 10 ' ) according to claim 1, characterized in that the means ( 24 . 32 ) for measuring a physical quantity, measure the current intensity of the current flowing through the current path, and in that - the electronic evaluation means ( 28 ) calculate the time derivative of the current, and that at least one predetermined phase, the behavior of the time derivative of the current in a short circuit was determined empirically and the actual behavior is compared with this empirical behavior, and / or - the electronic evaluation means ( 28 ) determine the time integral of the amperage square and use a threshold criterion. Circuit breaker or circuit breaker ( 10 . 10 ' ) according to claim 2, characterized in that at each predetermined phase and the behavior of the time derivative of the current intensity is determined empirically overcurrent and the actual behavior is compared with this behavior. Circuit breaker or circuit breaker ( 10 . 10 ' ) according to one of the preceding claims, characterized by a the actuator element ( 22 ) associated energy storage for supplying energy for the action of the actuator element ( 22 ) to the contact point ( 16 ). Circuit breaker or circuit breaker ( 10 . 10 ' ) according to one of the preceding claims, characterized by an interface via which the electronic evaluation means ( 28 ) from the outside data can be fed.