SU547907A1 - Device for forced switching of controlled valves - Google Patents

Description

(54) DEVICE FOR FORCED COMMUTATION OF CONTROLLED VENTS

The proposed device relates to the field of electrical engineering and is intended for the forced isolation of controlled valves (for example, thyristors in the event of a short circuit in the electrical network).

The known device (1 T1 main and auxiliary thyristors and a switching capacitor.

The disadvantage of this device is that the flow of short-circuit current in the switching circuit is prolonged}, the shock currents are limited weakly and require greater thyristor and capacitor power.

It is known device 2, which contains a successor} 10 connected thyristor, a capacitor and a two-phase transformer of excess energy output, the secondary winding of which is connected to the resistor.

The disadvantage of this device is the inhibition of the process of switching the current from the short circuit to the switching circuit, as well as the output of the energy of the precharged switching capacitor battery.

The aim of the invention is to reduce the tripping time of lockable thyristors and limit the short-circuit shock currents.

This is achieved by the fact that the device is additionally supplied with a choke and a diode, and the excess energy output transformer is three-wound, with a third winding connected to the power terminals by a direct current through the choke and the secondary winding in the reverse direction to the diode.

The drawing is a schematic diagram.

devices.

It contains a main thyristor, a switching capacitor 2, an auxiliary thyristor 3, a transformer for outputting a beating power source with a primary winding 5, a secondary 6 and a third winding 7.

The capacitor is connected by resistance I and diode 9. A parallel secondary winding 6 is connected to diode 10 and resistance 1. Consistently with the third winding 7, choke 12 is turned on.

Mouthfulness works as follows.

With a short circuit in the electrical network

control impulses are removed from the power thyristor 1 from the overcurrent sensors and thyristor 3 is opened.

 : l K -.- plMKOK .1К; 11 OTHERS FROM IKIIK POWER IHIll., i.vpj I u commutating circuit 2, 5, 3. I paic. (|) The sender 4 starts peremagni shvats (ib (d; stop excess energy output from the switching circuit) after the current switching process is completed, when reverse leakage starts to flow through the power thyristor 1.

The magnitude of the setpoint current of the transformer 4 is determined by the number of turns in the windings 5, 7 and the bias current.

Prior to the reversal of transformer 4, the inductive resistance of the switching circuit is small, thereby ensuring a high rate of increase in the discharge current of the capacitor battery 2. 1 As the switching current passes through the switch, the thyristor 3 closes. In order to avoid the release of energy into the switching circuit during reverse switching of the transformer 4 under the influence of a bias current, the winding 6 is shunted by a diode 10.

When the capacitor 2 is recharged (the polarity changes), part of the energy is dissipated in diode 9 and resistor 8. Thus, the level of overvoltage on the power thyristor 1 is reduced.

Feasibility, the effect of using this invention is to increase reliability, reduce the cost and the installed capacity of electrical installations.

The invention of the Device for switching commutator controlled valves, contains a capacitor, auxiliary controlled valve 5 Dvuhmobmotochnn, an excess energy output transformer from a switching Koirrypa, the secondary winding of which is connected to a resistor, characterized in that With the aim of modernizing the reliability of the device by limiting the shock current of a short circuit, it is additionally equipped with a choke and a diode, the excess energy output transformer is made with a three-winding one third Through the choke, the cable is connected to the supply terminals with a constant current, and the secondary winding is back-bounded by a diode.

Sources of information taken into account in the examination:

1.Mogilevsky G.V., Grebennik V.I. Ultimate switching capacity of contactless

power switches .., Electrical Engineering, No. 6.1974 g., p. 9-I.

2.Labuntsov V.A., Zabrodin Yu.S. Transformer output of excess energy from the switching circuit of a thyristor and voltage oscillators

Electrotechnical industry. Seri Conversion Technique Vol. 9-10. 1970, pp. 9-13 (prototype).