SU736256A1 - Resistance relay - Google Patents

Description

one

This invention relates to relay protection of power systems.

Power relays and power directions are known, which contain blocks of coincidence of the signs of two sinusoidal electrical quantities and are based on the principle of comparing the time of coincidence with a given time, I and 2, or the mismatch time 3.

Relays built according to the first principle require the use of pulse expanders. In order to reliably eliminate vibration, the impulses must be extended by a time longer than a period of T 20 ms, which reduces the noise immunity of the relay and increases the time it takes to return. The relay, built on the second principle, is characterized by a pronounced dependence of time and action on the phase difference.

A relay is known in which the vibration and cutting time dependence of the action on the phase difference is fundamentally eliminated 4 and 5. Its peculiarity consists in the separation of the operation and return functions and their transfer to different blocks. The specified relay contains an input adder that forms the measured value.

 2

an integrator, a null indicator, an inverter, a threshold element, and a return unit for setting the integrator to zero (a fast integrator discharge). in cases where this relay is used as a resistance or power direction relay, the return unit is in the form of a two-wave half

10 phase-sensitive organ connected to the input setting the integrator to zero.

However, this relay does not have high noise immunity, it falsely triggers when sign-constant signals are applied to its inputs. In addition, the return unit is made in it so that it responds to the pro2C duration of the mismatch intervals, as a result of which the relay triggers falsely if a higher frequency signal is applied to its input. The purpose of the invention is to increase

25 noise immunity relay.

The goal is achieved by adding a block of positive values and a block of negative values of the compared values, an integrator, a voltage limiter, a two-stage voltage divider and a full-wave phase-sensitive organ in the relay containing an adder, an integrator and a threshold element, and the output of each of the matching blocks positive and negative values of the compared quantities are connected to the input of the corresponding integrator and to the inputs of the two phaseper-phase-sensitive body, the output of which is connected to the inputs of the installation of zero integrators, and their outputs are connected to the inputs of the adder and voltage limiter, the output of which is connected to one stage of the voltage divider, to another stage and midpoint of which the corresponding inputs of setting the threshold values are connected and the return of the threshold element, the input of which is connected to the output of the above adder, and the output is the output of the device.

Fig, 1 shows a functional diagram, a relay; in fig. 2 are diagrams illustrating its operation in the zone of operation; Fig, 3 - diagrams characterizing the behavior of the relay when exposed to interference.

The device contains blocks 1 and 2 of coincidence of positive and negative values of the compared values, integrators 3 and 4, adder 5, voltage suppressor 6, two-stage voltage divider 7, threshold element 8, full-wave phase-sensitive organ 9.

An additional integrator creates a second measurement channel, and the relay only works if the measurements in both channels give a positive result. It follows that the proposed relay can be given as high noise immunity as the double phase comparison relay 6, but since the level of limiting the output voltage of the integrators and the trigger voltage of the threshold element are increased, higher noise immunity is provided.

If a known adder is installed at the input of a relay, i.e., an integrator, and is intended to form a measured value from two input values, then the proposed relay adder is connected between the integrators and the threshold element and is intended to compare the sum of the output voltages of the integrators with the voltage tripping and returning the threshold element.

If the voltages U and Ug are equal to zero, the voltage O at the outputs of blocks 1 and 2 matches a zero or perhaps a negative level. As a result, zero

the level and voltage at the output of the phase-sensitive organ 9, the integrators 3 and 4 are at the same time discharged, i.e., are in the zero position, and the voltage (, (4 also have a zero level. A voltage of the same level arises and the output is the sum of the fopa 5: 0 oh. But the thresholds and the return thresholds of the threshold element 8 exceed the zero level; the trigger voltage Q is U –U QtU, where a and is the direct voltage drop across the diode in the trigger voltage setting circuit, and return Upj, U jj-AU, where they were - my

voltage drop across the diode in the circuit

voltage return settings. If we take into account that Uf, (it is chosen larger than the value and, it becomes clear that in the considered mode the threshold element must be in an unstable state, and the voltage Uj-o at its output has the maximum possible positive level corresponding to the failure of the relay. If both are fed to the pele inputs

5, the values 0 and Uj and the interference is absent, then sinusoidal voltages are applied to the inputs of blocks 1 and 2 (Fig. 2). At intervals of coincidence of their voltage signs Ug or

0 will have a positive level and the full-wave phase-sensitive organ 9 comes into action. Let Revenge the phase difference of the voltage U and U, the phase-sensitive body 9 works in the range

 corners - where the border of the working area.

The integrators 3, 4 take effect only after the two-full-phase phase-sensitive organ 9. triggers. Together with the adder 5, the limiter b and the threshold element 8, they form the measuring part of the relay, which ultimately determines whether it should work. But the return of the relay is completely determined by the full-wave phase-sensitive organ 9, since when it is returned the integrators 3, 4 almost instantly sink into the zero position of the threshold element 8, and if it worked before, it immediately returns

In the coincidence intervals of the signs of the 5 voltages U and U, the integrators 3, 4 are alternately charged with a time constant G, i.e. the voltages Up, j increase linearly, since the determination of the width of the working zone can be assigned to the phase-sensitive organ 9, at intervals of non-comparison of voltage signs and Uj, the integrators 3, 4 can maintain their voltage level unchanged, as in the well-known

(Fig. 2). However, it is possible, if necessary, to discharge integrators 3, 4 over mismatch intervals with a certain time constant tp, to obtain an adjustable dependence of the response time on the phase difference H

If the relay contained only one integrator, then under the influence of interference, which triggered the response of the photosensitive organ, it could be charged to the trigger level of the threshold element, which would lead to a false triggering of the relay. But in the proposed relay, such a danger is excluded, because limiter 6 does not allow one of the integrators 3 or 4 to lift its own. the output voltage is enough to trigger the threshold element 8. The voltage is limited by the threshold UorrU o LO, where is the direct voltage drop on one of the diodes of the limiter 6. If the output voltage of one of the integrators 3 or 4 has reached the threshold - . p, then the output voltage U of the adder 5

.and

eo

will be W / p / 2.- But the threshold of the threshold element 8 is set in such a way that the inequality j exists (p UQpp / 2. And the condition .. p leading to the operation of the relay will add up only if During one of the integrators, a voltage is added at the output of the second integrator, although less Uopf, but still large enough to prevent the false operation of the relay. And there is always the possibility to lift the threshold U (. ( a slight increase in the response time of a noticeable increase in relay resistance (Fig. 2). Of course, the value should remain smaller.

The full-wave phase-sensitive organ 9, generally speaking, can be constructed by any method. The only requirement for it is that in the working area Uex) Hj3 its output voltage is continuous / Vibration of the phase-sensitive organ 9 at the edge of the working area is permissible, since in this case integrators 3, 4 are periodically discharged and cannot develop voltage sufficient to operate the threshold element 8.

The implementation of the phase-sensitive organ 9 by comparing the coincidence time with the duration of mismatch intervals specified by one-time control further enhances the interference7 stability of the relay, since the duration of each time interval is checked, namely, if the coincidence intervals exceed the specified value of 6 tj. and the mismatch intervals, on the other hand, do not exceed the three ut ut value.

The use of this resistance relay in distance protection increases its noise immunity, as a result of which the likelihood of over-trips and protection failures is reduced, and the NTO as a whole increases the reliability of consumer supply.

Claims (6)

1. Author's certificate of the USSR M 146843, cl. H 02 And 3/38, 1961.. 2. USSR author's certificate number 480134, cl. H 01 H 83/16, 1973. 3.Patent UK  1374425, cl. H 02 H 3/40, 1974. 4. USSR Copyright Certificate No. 462229, cl. H 01 H 83/00, 1973. 5. High-speed, automatic reclosing device of 750 kV overhead lines of Type APV-750. Report VNIIE number 73013627, M., 1974. 6. C, Iodgollo, L.Weacpone. Resistance relay based on the principle of dual phase comparison. performed on semiconductor triodes. Sat Semiconductor triodes in hardware. relay zayshty, measurements and telemechanics for power systems. M., Gosenergoiedat, 1958, p. 41-49. U, ac, fo -do h with fo / o tit5