SU997116A1 - High-voltage ac switch - Google Patents

Description

(.54) AC HIGH-VOLTAGE SWITCH

The invention relates to electrical engineering, specifically to high-voltage switching devices of alternating current with a large number of switching.

Known high-voltage switch AC, containing the main contacts, parallel to which included a branch of semiconductor devices, current transformers, first. the primary windings of which are included in the circuit of the main contacts, and the secondary windings are connected to the control. Electrodes Cll.

The disadvantage of this switch is the presence of a large number of thyristors.

The closest in technical essence and effect to the invention is a high-voltage AC switch containing main contacts, shunted by a chain of opposite-connected thyristors with protective RC circuits, a mechanical disconnector connected in series with the main contacts, current transformers, secondary circuits which are included in the control circuits of the thyristors, and primary - in the circuit of the main contacts 2.

This switch has the same drawbacks as the previous one.

The aim of the invention is to increase the life and reliability of the switch.

The goal is achieved by the fact that in the device, in addition to the chain of thyristors, included in addition,

10 contacts of the vacuum arc chamber and the primary winding of the current transformer, the secondary winding of which is connected to the winding of the electromagnetic drive.

15

A limiter, such as a varistor, is included to limit the overvoltages across the thyristor circuit in parallel.

The circuit breaker is shown on

20 drawing.

The switch contains main contacts 1, controlled by drive 2, phase shifting device 3, voltage limiter 4, transformer

25 current 5 and pulsed peak transformer 6, two anti-parallel thyristor 7, vacuum arcing cable Kgmeru 8, which controls the drive that feeds .: from

30 current transformers 9 and rectifier Horb bridge 10, protective RC circuits 11, varistfur 12 and disconnector 13.

The switch works as follows.

After the command is issued, the Start and Phase-shifting device 3 Slip I1 1 and 0 peak-transformer 6 is applied to trigger the prism 2. The purpose of moving the pulse from the transformer 6 is through phase shifting (the receiving device 3 and issuing it to 0 in time to drive 2 is to ensure synchronization of unclosed pins 1 in; the beginning of the C01 “start of 1-in. current,

 how to live on. contacts 1 reaches a value sufficient to switch on one of 7 (2-3 V, in contrast to the switching voltage of Tsper, successively connected prototype thyristors of the prototype and per) and by means of a trans-20 transformer 5, switching of one of the semiconductor devices into the wire The current state and the current passes from the main circuit of the contacts 1 to the auxiliary arc circuit. 25

Simultaneously with the appearance of the current in the thyristor circuit, the current transformer 9, via the rectifying bridge 10, sends a signal to the electromagnet winding of the high-speed drive, designed so that the contacts of the vacuum chamber 8 occur in the immediate vicinity of the zero current, (1 -1.5 ms Thus, a double-synchronization of the switch operation is carried out: the main contacts 1 are initially opened at the beginning of the current half-cycle and the vacuum contacts of the extinguishing chamber at the end Q of the same half-period.

After the current passes through zero at the contacts of the vacuum chamber, with an advance of 10-15 MKS (the recovery time of the thyristor's locking ability), the voltage begins to recover in comparison with the thyristor. After 10–15 MKS, the voltage on the semiconductor device is restored. By this time, almost all the voltage will be applied to the 50 break of the contacts of the vacuum chamber 8 (the voltage recovery rate for such devices when the rated currents lie within 2-4 kV / µs). In addition to the synchronous opening of the contacts of the vacuum chamber 8, the arc energy emitted at the contacts is substantially less than, for example, at its one half-period release in the case of traditional device operation. Therefore, the gap is deionized: even faster. When the voltage on a locked thyristor is restored, its rate of increase is limited to 45

Ke-chain MI 11 and quite freely can be reduced to units of volts per microsecond. In order to improve the reliability of the thyristors at possible overvoltages of the network, varistor 12 is connected in parallel with the semiconductor set-top box. It limits the peak of the overvoltage to a permissible value chosen in accordance with the passport data of semiconductor devices.

After the voltage has been restored, the disconnector 13 is broken at the contacts of the vacuum chamber 8.

The device is turned on by the disconnector 13 at the closed contacts 1 and the contacts of the camera 8, which are closed in the specified sequence after the termination of the shutdown process.

The efficiency of such a device, besides a significant increase in the switching resource of the main contacts and reducing the number of thyristors (from pyristors depending on the class of the device for voltage up to two), also includes the fact that during the flow of rated currents and short-circuit currents and shunt branch no current flow and only works in switching mode. At the same time, the short duration of operation of the chamber 8 allows the use of vacuum chambers designed for relatively small currents (e.g., high pressure switch -10-400, high pressure switch -10-160) for frequent switching of currents of 10-20 kA.

The greatest efficiency in the use of this annapaTci can be achieved as a result of its installation in relatively low-voltage circuits of 10-35 kV, in particular, in the power circuits, with the need for frequent switching of large nominal currents.

Claims (2)

1. A high voltage alternating current switch containing the main contacts easuntized with a counter-connected parallel thyristors with protective KS circuits, a mechanical disconnector connected in series with the main contacts, TOKEI transformers, whose secondary windings are included in the thyristor control circuits, and the primary coils The main contacts, characterized in that, in order to increase the resource and reliability, additionally introduced vacuum contacts quarantine chamber and primary: the winding of the current transformer is secondary, the coil of which is connected to the winding of the electromagnetism of the chamber. 2. The switch according to claim 1, about t l and: h and y c and and the fact that parallel to the shunting branch of thyristors , reenactment delimiter enabled, Gnapri "er varistor. Sources of information I taken into account in the examination 1. USSR author's certificate 342235, cl. H 01 H 9/30, H 01 N. 33/04, 1970. 2. Authors certificate of the USSR 641528, cl. H 01 H 33/59, 1975.