SU1252859A1 - Current relay - Google Patents

Abstract

The invention relates to the field of electrical engineering, in particular, to relay protection, and is intended for use in high voltage power line relay protection devices. The aim of the invention is to increase the speed of the relay. With an aperiodic change in the signal at the input of the comparative part, the return time of the relay does not exceed the return time of the one-shot 5, which, in the absence of the splitting scheme in the conversion part 2, is chosen close to half the period of the power frequency signal. The introduction of an organ 4 for comparing the durations of the stay of the comparator in the states of operation and non-operation and the logic element Ib reduces the return time of the relay and thereby increases its speed of operation. 1 hp f-ly, 3 ill. (Lu 00 ate about figure 1

Description

II

The invention relates to electrical engineering, and particularly to relay protection, and is intended for use in high voltage power line relay protection devices (VL).

The purpose of the invention is to increase the speed of the relay developed by B. decreasing the relay return time.

FIG. 1 shows the structural scheme of the proposed relay; in fig. 2 is an example of the implementation of its retarding part; in fig. 3 is a timing diagram explaining the operation of the proposed relay, where the supply voltage,

and.

i signal at the input of the relay i;

the output signal of the transforming body Ur, 4; the signal at the comparator output; the signal at the output of the comparator's duration of the comparator's stay in the tripping and non-operating states (DSS) U; single output signal. and „; signal output circuit AND U,.

The input of the sensing part 1 of the proposed relay is connected to the input current sensor ij. The output of the sensing part 1 is connected to the input of the transforming part 2, the output of which is connected to the input of the comparator 3. The outputs of the comparator 3 are connected to the body of the comparison of the duration of the stay of the comparator in the operating and non-operating states of the DGD 4 and the generator 5 6. The output of the circuit And 6 is connected to the input of the executive part 7.

The retarding part of the proposed. The relay (Fig. 2) of the DSD 4 is made in the form of an integrator formed by a resistor 8 and a capacitor 9, to the output of which a second comparator is connected, which is a Schmitt trigger based on operational amplifier 10 Due to connections through diodes 11-14 thresholds the triggering and returning of the Schmitt trigger, as well as the ultimate voltage at the integrator output (at the capacitor 9) is determined by means of a divider formed by resistors 15-20. The Schmitt trigger is triggered when the voltage on the capacitor 9 exceeds the trigger trigger threshold, and the return occurs when the specified voltage drops below the triggered return threshold. Thus, due to iner252 .8

i

u - 15

20

25 ZO,

59

properties of the integrator, both the actuation and the return of the OLD 4 are generated with a delay compared with the switching times of the comparator 3.

The one-shot is made by means of a limiter for the duration of the signal and the time-delaying organ (OVV), which provides a return delay. The signal duration limiter includes a differentiating circuit consisting of resistors 21 and 22 and a capacitor 23, and a comparator on the operational amplifier 24 connected to the output of the specified circuit (to resistor 22). The threshold of operation of this comparator is determined by the voltage drop resistor 25, which, together with resistor 26, constitutes a voltage divider. The return for OVV consists of a diode 27, resistors 28 and 29, a capacitor 30, and an operational amplifier 31, which performs the function of a comparator, triggered when the voltage across the capacitor 30 is zero;

The circuit And, the inputs of which are connected to the outputs of the OSD and the one-shot, implemented through diodes 32 and 33 and the ballast resistor 34.

The relay works as follows.

With the input signal „0 kompak

The rator 3 is in an idle state, as a result of which all the organs of the retarding part 4-6 and the executive part 7 of the relay i.e. at the outputs of all these parts and organs there are logical signals O.

At time t (Fig. 3) a short-circuit occurs. Signal 1 „starts to increase,

RL

which causes an increase in the signal and ,, y, which is constructed in relation to the case when the transforming part 2 carries out the rectification of the signal arriving at its input. At time t, the signal starts to exceed the trigger threshold of comparator 3, which leads to the triggering of comparator 3 and one-shot 5. However, the AND 6 circuit does not trigger, as the DSD 4 continues to remain in the non-working state. At time tj, the duration of the continuous stay of the comparator 3 in the state

actuation exceeds the value required for DSP 4 to trigger and DGN 4 is triggered. On both inputs of the circuit: And 6 logical signals are installed.

ly 1 that causes the appearance of a logical signal 1 at the output of the circuit 6 and the response of the executive part 7 of the relay.

At time t, comparator 3 returns, which remains in a state of failure until t-. However, the return of OSD 4 and one-way-paTQpa 5 is not appropriate, since the duration of the interval (t, -t) is less than the values needed to return the indicated organs.

At time t ,; the comparator 3 is triggered again. The indicated one ensures the single-shot 5 is triggered and the DSD 4 is triggered. Thus, logical signals 1 are stable at both inputs of the AND 6 circuit, resulting in the AND 6 circuit and the executive part 7 of the relay being in the state triggered.

At time t, the fault is turned off. Signal

ly 1 and

and

begin to decline

to zero. Despite the fact that due to the gradual nature of this reduction, the comparator 3 stays in a sufficiently long state (until t), the conditions for the repeated (after t,) start of the one-shot 5 do not occur. At the time t (where T is the delay on the return of the one-shot) it returns. This causes the appearance of a logical signal O at the output of the circuit And 6 and the return of the executive part 7. At time t, the DLA 4 returns to the logical inputs of both the circuit And 6 and the logical signals are set.

et.

10 OST)

 - the time of the return of the OSD 4 with a stable stay of the comparator 3 in the state of failure.

Thus, when using the proposed relay with the aperiodic nature of the signal change on

 ): to b94

the input cp1; iplcp1g of the length of the half-turn-over relay does not exceed the one-shot return time, which in the absence of the conversion part 5 of the splitting scheme is chosen close to half the period of the industrial frequency signal. When used in the conversion part of the splitting scheme, the return time of one oscillator and, accordingly, the return time of the relay can be further reduced.

Claims (2)

Invention Formula 15 1. A current relay containing a sensing organ connected in series, a transforming organ, a comparator, as well as a single vibrator and an executive organ, are e20 with the fact that, in order to increase the speed of the relay, a comparison organ has been introduced into it the duration of the stay of the comparator in the states of operation and non-operation and the logic element I, while the output of the comparator is connected to the input of the one-shot and to the input of the body comparing the durations of stay of the comparator in the states of 0 failure, single-output output and output of the comparator, the duration of the stay of the comparator in the states of operation and non-operation are connected respectively to the first and second inputs of the AND gate, and the output of the AND gate is connected to the input of the actuator. 2. The relay according to claim 1, that is, so that the organ comparing the durations of stay, of the comparator in the operation and failure states is made in the form of serially connected integrator and comparator, while the output of the comparator is the output of an organ comparing the duration of the stay of the comparator in the states of operation and non-operation.