SU681496A1 - Starter member for relay protection arrangement - Google Patents

Description

one

The invention relates to relay protection of elements of an electrical AC network and dp devices can be used, relay protection of network elements with a voltage of 500 - 750 kV.

A starting organ is known, each of the phases of which are measuring current and voltage transducers, quadrants, differentiation, adders and reactive unit l.

This device is relatively complex.

Starting bodies are known that react to the increment of an electrical quantity and contain the emergency component and the reverse sequence filters and the reacting unit 2 and h.

However, “these devices affect the deviation of the network frequency from the nominal, in addition, they are not sensitive enough. Consecutive connection of several filters of an emergency component increases sensitivity, but reduces speed.

The closest in technical essence to the present invention is a starting body for relay protection, including measuring transformers, voltage filters, phase shifters, differentiating bodies, rectifiers, and two-winding relay 4j. In this device, the signals taken from the current and voltage transformers are fed through direct and negative sequence filters and phase shifters to rectifiers. Rectified signals are differentiated and compared in a reactant organ made in the form of a two-winding relay.

However, the presence of passive filters and power converters at the input of the comparison circuit slows down the action of the triggering organ, complicates its adjustment and increases the size of the device. Such a device may work falsely from interference.

The purpose of the invention is to increase the sense of vitality.

Claims (4)

For this purpose, the proposed triggering device for relay protection, containing current and voltage measuring transducers included in each phase, and two differentiating units, the outputs of which are connected to the inputs of the executive unit, additionally introduced two chains, each of which consists of sequentially connected units nonlinear transducers made on quadrants and adders connected between the outputs of the current measuring transducers and the input of the first differentiating unit and between the outputs of the meter GOVERNMENTAL transducer voltage and the input of the second differentiating unit, respectively. The drawing shows a functional diagram of the proposed starting body. The DEVICE contains a Hbie current transducer 1 and voltage 2, blocks 3 guilinear current transducers and voltages for squaring electrical quantities, adders 4 tpka and voltage, differentiating current and voltage blocks 5, block 6 current and voltage zero indicators and logical element AND 7. Block 6 of zero-indicators and logical element And 7 form the executive body 8. Transmitters 1 of current and 2 voltage are connected to the inputs of block 3 of non-linear converters and voltage odes are connected to inputs of the adders 4 and AC voltage in the channel current in channel voltage. The outputs of the adders 4 current channels and voltage channels are connected to the inputs of differentiating units, the outputs of which are connected to the inputs of the zero-current indicators and the voltage of block 6. The outputs of the zero-indicators are connected to the inputs of the logic element 7. The device operates as follows. In a normal mode, voltages without a three-wire line form a symmetrical three-phase system of sinusoidal voltages that are out of phase through an angle of 120 °. The magnitudes equal to the sum of the squares of the instantaneous values of the voltages of the three phases and the TCs of the three phases measured at the outputs of the voltage capacitors 4 and the current channel using the block 3 nonlinear converters and adders 4, in normal operation, are balanced, unchanged in of time. The first value at the output of adders 4 in normal mode is zero both in the current channel and in the voltage channel. During a short circuit, due to a change in phase relations in the transient process between phase voltages and phase currents, changes in their amplitudes, the appearance of free component voltages, the balance of the sum of the squares of the voltages and the sum of the phase squares of the currents and the outputs Adders 4 in the channel TSSH and in the voltage channel appear values that change in time, the derivatives of which are not equal to zero. Therefore, at the output of differentiating unit 5, both in the voltage channel and in the current channel, there are different signals from the zero inputs to the inputs of the null indicators 6. The current channel null indicator compares the incoming signal with the setpoint and, depending on the excess, generates a signal from the inputs of the logic element 7. At its second input, a signal comes from the output of the voltage channel null indicator, which is produced depending on the voltage output from the differentiator of the voltage channel. At the simultaneous receipt of two signals from the outputs of the block of 6 null indicators to the inputs of the logic element And 7, a signal appears at its output that triggers the protection. In the presence of interference by the Voltage, a signal is generated coming from the channel zero indicator of the voltage to the input of the logic element AND 7, but due to the absence of a signal from the TCH channel on its other input, no protection is triggered. The same thing happens when noise gets into the current channel. Thus, the false triggering of the triggering organ in the absence of a short circuit on the protected object is eliminated. The device will allow to quickly start a relay protection with good noise immunity and, thereby, with a minimum time delay, localize the short circuit on the protected object. It will make it possible to increase the sensitivity of protection even in the presence of imperfections in phase voltage systems and currents. Its design has small dimensions to weight, due to the fact that at the input of the circuit there are no bulky in design and difficult to configure filters, for example, and booster devices. The use of the proposed device will increase the stability of power supply systems due to the accelerated disconnection of damaged objects and improve the quality of power supply. The formula of the Inventional and Starting Body for Relay Protection contains current and voltage measuring transducers included in each phase and two differentiating units whose outputs are connected to the inputs of the execution unit, characterized in that, in order to increase the sensitivity, two are additionally introduced chains, each of which consists of series-connected blocks of nonlinear converters, made on quadrants and adders, connected between the outputs of the measuring current converters and the input of the differentiating unit and between the outputs of the voltage measuring transducers and the input of the second differentiating power supply, respectively. Sources of information taken into account during the examination 1. L. U. Mopp, U. Mom & on, ISeEayin cf phase tranbmission Cme w / lh a digflat computer SHVET1GNAP &, on RLE-90, 1971, No. 2, p. 742-750. 2. Gelfand Ya. S., Zisman L. S, Detection of Damage in Electric Networks by Instantaneous Values of Emergency Components. Express info; - GAZI. Means and control system in power engineering, 1975, No. 1, p. 12-14. 3. Shneerson, EM, Fedorov, M. K, Launching organs of the relay interlocks are sewn up when oscillations are increased. Electric power stations, 1977, No. 7, 4. USSR author's certificate number 316149, cl. H 02 H 3/38, 1969.