High-voltage alternating-current switching composite switch capable of being switched on and switched off in completely zero-voltage closed mode

Abstract

The utility model discloses a high-voltage alternating-current switching composite switch capable of being switched on and switched off in a completely zero-voltage closed mode, and relates to the field of switches of high-voltage alternating-current power grids. N sets of unidirectional silicon controlled rectifier valves are connected with N sets of diodes in series to replace N sets of bidirectional silicon controlled rectifier valves which are connected in series originally, alternating current inputs a voltage waveform signal of the alternating current to the optocoupler through a step-down circuit, the output of the optocoupler is connected with an I / O interface of a single-chip microcomputer, after the single-chip microcomputer receives an external conduction signal, the single-chipmicrocomputer identifies a half wave cut off by a diode string of a power grid auxiliary loop and delays for 3ms, and outputs a signal for controlling the conduction of the unidirectional silicon controlled rectifiers, and all unidirectional silicon controlled rectifiers can be completely conducted in the half wave and wait for the next half wave, the diode group is naturally conducted, the auxiliary circuit is conducted, the single-chip microcomputer delays 7.5 ms from a zero point after identifying a negative half wave, an instruction is sent out to conduct an alternating-current vacuum contactor, and the auxiliary conduction circuit is a multi-string silicon controlled rectifier valve group capable of meeting the voltage level and a multi-string diode series group.

Description

technical field [0001] The present invention relates to the switch field of high-voltage AC power grid. To be precise, it is a kind of auxiliary circuit that is turned on in the state of no current. After the circuit is turned on, the auxiliary circuit is disconnected and applied to the high-voltage switch of the AC grid. It is a high-voltage AC switching composite switch that is completely zero-voltage closed and turned on and off. Background technique [0002] Switches in the AC medium and high voltage field include vacuum contactors, vacuum circuit breakers, oil switches, etc. When these switches are switched directly with load, the large inrush current will have a large impact on the power grid, and the number of switching operations can be small. [0003] Another is to use multiple sets of thyristor valve groups in series as the auxiliary switching circuit, which is turned on at the zero point of the AC voltage, and then the vacuum contactor or vacuum circuit breaker is...

AI Technical Summary

Problems solved by technology

But it still has flaws, multiple silicon controlled rectifier group valves are connected in series, because the response speed of silicon controlled rectifiers is in the microsecond level, which is enough to achieve zero-point conduction of 50Hz AC grid voltage, but there is still a problem of conduction sequence after multiple groups of valves are connected in series. In theory, the last conduction still has to carry the entire voltage, so this structure still has great limitations in the high-voltage field, and the problem is especially serious when the voltage level is too high or the capacitive load

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