SU70326A1 - Device for testing high-voltage switches - Google Patents

Description

The subject of the invention is a device (artificial circuit) for testing high-voltage disconnecting switches with separate sources of test current and voltage and with switching on the source of test voltage through a spark gap.

The essence of the invention is that the electrical relay, igniting the spark gap, is connected via amplifiers to connected in series active and inductive shunts in the short circuit circuit (current c. H.) In order to change the moment of applying the test voltage by adjusting the coefficient amplification amplifiers.

FIG. 1 is a schematic diagram of the power circuit of the proposed device; FIG. 2 is a diagram of the igniter pulse supply circuit and in FIG. 3 is a diagram of current variation in the circuit.

Through the test object IR and the auxiliary break BP transmits a short circuit current from the source Gt with a relatively low voltage sufficient

to provide an undistorted current waveform K. 3. The magnitude of the current is controlled by reactor P.

At the time of passage of current through zero, the arc in the intervals of the IR and BP extinguishes. At this moment, an additional device ignites the spark gap F, through which a high voltage source G is connected to the test object. By changing the parameters of this source (shock circuit, step-up transformer, powered from the source Gt, etc.), you can adjust the maximum value and speed of the restoring voltage.

The BP gap serves to protect a low voltage source from high voltage pulses entering it. As the BP can be used the free phase of the test object.

In the known systems, the ignition of the spark gap F is effected either from the peak of the arc quenching in the MI, or from the relay triggered at the moment current passes through zero. In this case, a pause is obtained between the moment of arc interruption in the MI and the moment of application of high voltage to it. This pause is determined by the intrinsic operating time of the ignition circuit F. The presence of this pause greatly reduces the value of the test. In the proposed scheme, this pause can be reduced to zero. The idea of the circuit is as follows. Let it be necessary to obtain a steep voltage pulse from the corresponding relay device, leading by zero seconds the moment of current passing through zero, and this value should not depend on the current value and on the presence or absence of a periodic component in it. As the experience of previously implemented schemes shows, t has a size of about 100-150 villages :. di (i L i (i t dt, Included in the circuit of the circuit h., measuring shunt - ohmic R and inductive L (dashed line in Fig. 1) - and taking the sum of the voltage drops on them, we get (Fig. 2) that the voltage between the points a and c + L -§. (3) The right part of equation (3) has the form similar to expression (2). Strengthening the components of this voltage Uab and Ubc-I i with the help of amplifiers Y and then adding them, we get: .Uab + - 1, where KI and 2 are the gain factors of the amplifiers Ki and Kz. The voltage U is fed to the zero electronic relay ER. The relay will operate when 0 0, i.e. when k, L + k , Ri 0 2 (fi, ir, + Of compared and expressions (6) and (2) show that the ratio (6) takes place at the moment preceding the passage of current through zero for r seconds, and that k L k IT By adjusting the gain coefficients KI and K2 of amplifiers, it is possible to change the value of m. The output of the electronic relay must receive a steep voltage pulse, from which the spark gap F is ignited. The pulse supply circuit must have a blockage that ensures that the pulse is fed to the gap F only if there is voltage on the arc, i.e., the contacts have already opened. Such locks exist and their implementation does not present any difficulties. Apparatus for testing high-voltage circuit breakers with separate sources of test current and voltage and switching on the source of test voltage through a spark gap, characterized in that the electronic relay igniting the spark gap is connected through amplifiers to connected in series active and inductive plugs in a circuit short-circuit current, in order to change the moment of supply of test voltage by adjusting the amplification factors of the amplifiers.

i

--PGZTPGIGGO

FIG. 2