Intelligent zero-crossing switching device for high-voltage shunt capacitors

Abstract

The invention discloses an intelligent zero-crossing switching device for high-voltage shunt capacitors. The intelligent zero-crossing switching device comprises a silicon-controlled rectifier group, single-pole alternating-current vacuum contactors, a controller, a photoelectric conversion system, a depth filter and a trigger board. The silicon-controlled rectifier group comprises first inverse parallel silicon-controlled rectifiers and second inverse parallel silicon-controlled rectifiers, Phases A of the first inverse parallel silicon-controlled rectifiers are serially connected with one another, phases C of the second inverse silicon-controlled rectifiers are serially connected with one another, the single-pole alternating-current vacuum contactors include phase-A single-pole alternating-current vacuum contactors and phase-C single-pole alternating-current vacuum contactors, and the photoelectric conversion system comprises photoelectric converters and transmission optical fibers and has a main function of carrying out photoelectric signal conversion on electric signals between the controller and the trigger board of the silicon-controlled rectifier group; the trigger board is connected with a control pole of each silicon-controlled rectifier and is used for outputting trigger signals required for triggering the silicon-controlled rectifier group, voltages signals of the phases A and phase lines B and voltage signals of the phases C and the phase lines B are transmitted through the depth filter and then are connected with the controller, and the controller is connected with the trigger board by the photoelectric conversion system. The intelligent zero-crossing switching device has the advantages of high voltage zero-crossing detection precision and good switching effect.

Description

technical field [0001] The invention relates to an intelligent zero-crossing switching device for a high-voltage shunt capacitor, belonging to the field of reactive power compensation. Especially suitable for intelligent switching of 10kV and other high-voltage reactive power compensation equipment. Background technique [0002] At present, the switching of the compensation capacitor in the 10kV line substation adopts ordinary switches, which cannot realize intelligent zero-crossing switching. Therefore, the switching of the capacitor will generate a large transient impact voltage on the system, the capacitor body, and the switching switch. current. Frequent non-zero-crossing switching of capacitors will lead to: a substantial increase in the failure rate of switching switches, a significant increase in the failure rate of compensation capacitors, and frequent tripping of frequency conversion device protection, which seriously affects the safe production of users and brings...

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Problems solved by technology

However, since the thyristor group is used as a mechanical switch, it generates a large amount of heat in the closed state, so there are problems of high loss, large volume, and high cost.

[0004] Patent 200910250652.x proposes a solid-state composite switch device. The composite switch device provided is a three-pole contactor structure. The three-pole contactor can only complete single-phase zero-crossing, and its voltage zero-crossing switching method is not specified. , using the general voltage zero-crossing detection method, the error is large, and it is easy to cause the intake of interference noise

In addition, the existing zero-crossing switching devices all collect the phase voltages of phase A and phase C. Due to the problem of the midpoint or grounding, the phase voltage zero-crossing acquisition is inaccurate, and each phase voltage has external interference or noise. Waveform distortion makes zero-crossing detection more inaccurate

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