SU1640659A1 - Device for prolonging the arc burning time in synthetic tests of breakers - Google Patents

Abstract

The invention relates to high-voltage impulse technology. The purpose of the invention is to increase reliability. By introducing the second capacitor 7, the second resistor 6 and the third resistor 9 into the circuit, the current pulse from the discharge of the first charged capacitor 2 is close to rectangular with a flat top. This makes it possible to increase the reliability of the test switch 11 during the first zero-current transition and reliably prolong the arc burning time in it. 2 Il.

Description

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The invention relates to high-voltage impulse technology, namely, installations for testing high-voltage switches for switching capacity on synthetic systems, and can be used in discontinuous power laboratories and network test benches that are equipped with oscillating circuits.

The purpose of the invention is to increase reliability.

FIG. 1 is a schematic diagram of the proposed device in a synthetic circuit with a sequential current overlay; in fig. 2 are diagrams of short-circuit current if flowing through the disconnecting circuit, current pulse 1 and the discharge of the first charged capacitor, current pulse r from the discharge of the second charged capacitor and voltage U at the contacts of the switches.

The device diagram {FIG. 1) contains a series-connected .. controlled discharge 1, first charged capacitor 2, first reactor 3. shunted by the first resistor 4. second reactor 5 shunted by the second resistor 6 and second capacitor 7, and disconnecting element 8. Reactors 3 and 5 shunted by the third resistor 9. Between the disconnecting element 8 and the controlled glitter 1, the circuit of the disconnected current from the auxiliary switch 10 and the test switch 11 is switched on, as well as a circuit from the series-connected switching apparatus 12, the current-limiting eaktora 13 and source 14 of EMF power frequency. Parallel to the auxiliary switch 10, a high-voltage circuit is connected from the series-connected second controlled discharger 15, the second charged capacitor 16, and the fourth reactor 17.

The device works as follows.

From the special instrument of automatic control of experience (PAH), the corresponding commands are given to the sequence of operation of switching devices of the device circuit (Fig. 1) and recording devices (oscillographs). At the time point c (Fig. 2), a command is issued to turn on the contacts of the switching-on apparatus 12, after which a short-circuit current I flows through the contacts of the auxiliary switch 10 and the test switch 11. At the time ta, a command is issued to open the switches 10 and 11 and between their contacts the arcs with the voltages U across the arcs. At the moment of time t3 0.1 ... 1 ms, shortly before the time t4 of the first current transition And the short-circuit through zero, a command is issued to operate the controlled spark 1, which occurs

at the moment of ta. At the same time, the pre-charged first capacitor 2 is discharged through the reactor 3, the first resistor 4, the second reactor 5, the second capacitor 7, the second 6 and the third 9 resistors, the disconnecting element

0 8 and the electric arcs of the switches 10 and 11. The sharp rectangular front of this current pulse (HI, the increased duration of its flat top, as well as the chosen amplitude of the current pulse 1 and provide

5 reliable breakdown of the arc gap when the current approaches And to the first zero at the moment t / i. The polarity of the piercing current pulse must be opposite to the polarity of the current I to the first zero. When the current polarity changes, and after the zero at the moment, its further passage is ensured.

From this point on, the need to extend the arc time disappears and the disconnecting

5, the element 8 disconnects the current puncturing pulse forming circuit. At the time ts, a command is issued to turn on the second controlled spark switch 15, connecting the second charged capacitor 16 and the fourth reactor 17, parallel to the auxiliary switch 10 to further fulfill the required test conditions using a synthetic method with sequential imposition of an increased frequency current.

In the case of application for testing of circuit breakers with a parallel overlap of high frequency current in the electric circuit.

0 (Fig. 1) it is necessary to re-connect the capacitor 16 from node A to node B, and disconnecting element 8 to node B (instead of node A). From the time ts, the conditions of the test correspond to the known conditions of the test5 on synthetic schemes.

The advantage of the proposed device is that. that the current pulse obtained from it 1I is close to a rectangular with a flat top. This allows

0 to obtain an almost 100% probability of the arc gap of the switch being tested at the first transition of the zero zero current. consequently reliably provide an extension of time

5 arc firing during synthetic testing of high voltage switches, taking into account the variation of the response time of the switching on apparatus 12 and of the arrester 1.

In the proposed device, it is possible to reduce the charge voltage of the capacitor 2,

those. reduce the cost of a self-powered device, as well as reduce the number of high-voltage capacitors from which a battery of capacitors is assembled, shown in fig. 1 in the form of a single capacitor 2. Moreover, the charge voltage can be reduced by a factor of 2 or more, which will significantly affect the connection circuit of these capacitors and, accordingly, their number.

Claims (1)

Apparatus of the Invention A device for extending the arc time in a test switch during synthetic switch testing, comprising connected in parallel 0 3 a disconnecting circuit, a circuit of a series-connected controlled arrester, a first charged capacitor, a first reactor shunted by the first resistor, and a disconnecting element, in that, in order to increase reliability, an additional input is included between the first reactor and the disconnecting element the second reactor, shunted by a chain of parallel-connected additionally introduced second resistor and second capacitor, and in parallel by a chain of series-connected first and second pe Actor included additionally entered the third resistor. FIG. 2