SU385370A1 - DEVICE FOR FAULT DETECTION - Google Patents

Description

one

The invention relates to generator protection devices and can be used in power systems where self-excited synchronous generators with a static excitation system are used.

To detect a faulty generator operating in the system, a device is used that contains a measuring element on the maximum voltage relay and an actuator. However, this device does not always provide reliable detection of a faulty generator.

The purpose of the invention is to improve reliability when a failed generator is detected, the p-abot in the system. c) that goal is achieved by the fact that the measuring body is additionally equipped with a current direction relay, and a relay of the maximum permissible excitation voltage of the generator, the outputs of which, together with the maximum voltage relay, are connected to the actuator through a logic unit.

The logic block, depending on the combination of input signals, implements the function

a-e-f bs (+ A /)

- a signal equivalent to the maximum excitation voltage of the generator;

c is the signal equivalent to the maximum network voltage; c () is a signal equivalent to the generator reverse current and delayed for some time.

The drawing shows a device that contains the following functional elements; measuring unit 1, which includes a relay of maximum permissible excitation voltage of generator 2, maximum voltage relay of network 3 and current direction relay 4, logic unit 5, consisting of time element 6, element "NOT 7, element" And 8 , element “AND 9 and element“ OR 10, executive body //.

A malfunction of the generator operating in the system may have a double character: a sharp increase in the excitation voltage or the disappearance of the excitation voltage. As the excitation voltage increases on a faulty generator, the relays of the maximum permissible excitation voltage of the generator 2 and the relay of the maximum voltage of the network 3 are triggered. Executive body 11.

In this case, on a good generator, the maximum voltage relay of the network 3 and the current direction relay 4 operate. However,

The input element "AND 9" receives only one signal from the current direction relay 4, delayed by the time element 6 for some time V.At, since the element "NOT 7 does not pass the signal from the maximum voltage relay 3.

At the output of the element "And 9 the signal does not change and, therefore, the switching on of the executive body will not occur on a working generator.

When the excitation voltage disappears on a faulty generator, a current direction relay 4 is activated, the signal from which with a delay of time arrives at the input of the element "AND 9. Since in this case the network does not increase | the network voltage, then the output of the NOT 7 is the signal that is fed to the second input of the element "AND 9. If there are two signals at the input of the element" AND 9, the output of the element also appears to be a signal that is fed to the input of the element "OR 10. The element" OR-10 includes. eleven.

In this case, on a working generator, no changes are made, and the device remains in its original state.

Subject invention

A device for detecting a faulty generator operating in a system containing a measuring element on a maximum voltage network and an executive body, characterized in that, in order to increase reliability, the measuring body is additionally equipped with a current direction relay and a relay of maximum permissible excitation voltage of the generator The outputs of which, in conjunction with the maximum voltage relay, are connected to the executive unit via a logic unit.