RU2084037C1 - Switching device for by-pass reactor - Google Patents

Abstract

FIELD: electric engineering. SUBSTANCE: device is designed as multiple-break switch which has capacitance voltage scaling circuit, which contacts are by-passed with serial circuit of variable capacitor and spark gap. Said circuit has additional measuring transformer, which secondary winding is connected to control gate of by-pass reactor switch. In addition insulation transformer is inserted between measuring transformer and control gate. EFFECT: increased functional capabilities. 4 cl, 1 dwg

Description

 The invention relates to the field of electrical engineering, in particular to high-voltage electrical apparatus for switching a shunt reactor (SR), and can be used in switchgears with a multi-burst switch in the SR circuit, which can be switched off for a long time in the network operating mode, and when overvoltage in the network must be included.

A device for switching on a shunt reactor with a switch having arcing contacts and a separator, in parallel with which a spark gap is connected [1]
The disadvantage of this technical solution is the significant difficulty of its implementation with switches without separators, which are currently being manufactured both in the country and abroad.

A device for surge protection of longitudinal capacitive compensation devices is known, in which a spark gap and a resistor are connected in parallel with the contacts of the circuit breaker [2]
The disadvantage of this technical solution when using it for switching SRs is the need to change the design of the circuit breaker, since the separator circuit breakers currently manufactured do not have.

 It is also known a device for autonomous switching on of a ballast with a switch without a separator, but with an increased number of arcing breaks, parallel to which part of the spark gaps are installed [3] This technical solution is the closest to the claimed one. Therefore, it is selected as a prototype of the proposed technical solution.

 The disadvantages of this technical solution is the use of a more expensive device than a standard network switch for switching a switchgear, called a switch-disconnector, with independent control of each of its two parts (half poles), which leads to an increase in the likelihood of simultaneous disconnection of half poles and, as a result , to an increase in the likelihood of overvoltages at the contacts of the first half-pole of the switch-disconnector, and to an increase in the probability of failure of the switch-disconnector in the off chenii SR.

 The aim of the present invention is the autonomous inclusion of ShR during overvoltages in the network, as well as the limitation of overvoltages when the ShR is turned off by a general-purpose power switch.

 This goal is achieved by the fact that the switching device SHR, containing a multi-burst switch with a capacitive voltage divider, an on-off control key with an input for a turn-on signal and a spark gap connected in parallel to part of the arcing breaks, additionally contains varistors connected in series with the specified spark gap and connected in parallel other part of arcing breaks not shunted by the spark gap, as well as a meter included in the spark gap circuit first transformer, the secondary winding is connected to an input control switch for the signal to switch shunt reactor. Moreover, the specified measuring transformer can be made in the form of a current transformer, the primary winding of which is included in the spark gap circuit, and an isolation transformer or an insulating light guide is inserted between the specified current transformer and the control key.

 The drawing shows the proposed switching device of a shunt reactor, which shows a diagram of a device comprising arcing breaks 1 and a capacitive voltage divider 2 of a switch between a high voltage object 3 and a shunt reactor 4, shunting a varistor 5 and spark gap 6, as well as a current transformer 7 in the spark circuit gap 6, connected through an insulating element 8 with the switch control switch 9 of the switch. The drive 10 shown in the drawing and the communication scheme of the proposed device with an operating current source 11 and an automation unit 12 of the shunt reactor 4, as well as the switched objects 3 and 4 themselves are necessary to explain the operation of the device, but are not included in the claims.

 The device shown in the drawing, operates as follows.

 In case of overvoltages in the network exceeding the breakdown voltage of the spark gap, it breaks down and the SR is switched on (through the varistor) with the circuit breaker open. The breakdown voltage of the spark gap is taken to be slightly reduced (by 20 30%) compared to half of the allowable for insulation, because The voltage divider provides half the phase voltage in the spark gap. A lower breakdown voltage is adopted so that the connection of the ballast can affect the magnitude of the overvoltage.

 The operation of the spark gap fixes the measuring current transformer in its circuit and generates a signal to turn on the switch.

 When switching off the ballast in any of three possible cases (both arcing breaks are turned off simultaneously, the arcing gap shunted by the varistor is delayed, the gap shunted by the spark gap is delayed), the overvoltage at the switch contacts reaches 2.8 2.5 IF. The voltage at the spark gap in the first two indicated cases is 2 times less, but because it is higher than its breakdown voltage, then as a result all the contacts of the switch will be disconnected, the spark gap is broken and all the voltage will fall on the varistor.

 In the latter case (when the gaps delayed by the spark gap are delayed), the voltage at the switch contacts will also lie on the varistor. Thus, in any case, the varistor creates an almost dead-time pause for a significant part of the half-cycle of the alternating current, which ensures the extinction of the arc in the spark gap and the successful shutdown of the ballast. The maximum current value in the considered shutdown mode does not exceed 100 300 A.

 When the short circuit is disconnected on the SR, the disconnected current is two orders of magnitude higher than when the operating current is turned off. The recovering voltage at the switch contacts can cause a breakdown of the spark gap in this mode. However, the varistor, connected in series with the spark gap, will reduce the current to values of the same order as in the mode of switching off the operating current of the SR. For reliability, known spark gaps with a moving arc can be used, which have an increased arc extinguishing ability.

 The proposed technical solution will find application in switchgears with shunt reactors, which in the operating mode of the network can be disconnected for a long time, and when overvoltage in the network must be turned on, because are one of the elements of a surge suppression system.

Claims (4)

 1. The switching device of the shunt reactor, containing a multi-burst switch with a capacitive voltage divider, an on / off control key with an input for a turn-on signal and a spark gap connected in parallel with part of the arcing breaks, characterized in that it further comprises varistors connected in series with said spark gap and parallel to the other part of the arcing breaks, as well as a measuring transformer included in the spark gap circuit, whose secondary winding is Dinen with the input of the control key for the signal to turn on the shunt reactor.  2. The device according to claim 1, characterized in that the measuring transformer is made in the form of a current transformer, the primary winding of which is included in the spark gap circuit.  3. The device according to claim 2, characterized in that an isolation transformer is inserted between the current transformer and the control key.  4. The device according to claim 2, characterized in that between the current transformer and the control key is switched on an insulating fiber.