Overvoltage rapid protection circuit and method for series capacitor of power system

Abstract

The invention relates to overvoltage rapid protection circuit and method for a series capacitor of a power system. The protection circuit comprises a series capacitor group and a metal oxide arrester (MOA) branch, a voltage sensor and a switching branch, wherein the MOA branch is connected in series with the series capacitor group and comprises an MOA and a current sensor which are arranged in series, the switching branch comprises a damping circuit and a switching device which are arranged in series, a main loop where the series capacitor group is located is provided with a main loop current sensor and a main loop voltage sensor, the main loop current sensor, the main loop voltage sensor, the current sensor and the voltage sensor are connected with an input end of a controller, and an output end of the controller is connected with the switching device. According to the protection method, main protection on overvoltage of the series capacitor group and thermal breakdown of the MOA is achieved by monitoring and rapidly identifying the current of the MOA branch, and backup protection on the overvoltage of the series capacitor group and the thermal breakdown of the MOA is achieved by monitoring the current of a main loop and the voltage at the two ends of series capacitor group. The protection circuit and the protection method are simple, direct, rapid and reliable.

Description

technical field [0001] The invention relates to the field of power system series compensation, in particular to a power system series capacitor overvoltage rapid protection circuit and method, which are mainly used in power systems and other industrial power systems for long-line, low-voltage, high-loss transmission and distribution lines. Loss of pressure regulation and improve transmission power. Background technique [0002] When a short-circuit fault occurs on the load side of the power system series compensation device, a high power frequency overvoltage will appear on the series capacitor. In order to avoid the damage of the series capacitor caused by this overvoltage, it is necessary to quickly protect it. [0003] The first device for overvoltage protection of series capacitors is the MOA. Due to the thermal capacity of the MOA and its own cost limitations, once the MOA operates, its safe working time is very limited, so it is necessary to set the second protection d...

AI Technical Summary

Problems solved by technology

[0004] The limitations of the prior art methods are: (1) the rapid identification of the acquired signal needs to be realized through a complex special algorithm, and misjudgment is prone to occur under the action of electromagnetic interference or transient interference signals; (2) the capacitor bank second The overvoltage protection device essentially protects the MOA, that is, it needs to quickly bypass the activated MOA, so the above signal is only an indirect signal, not a direct signal for the capacitor bank or MOA to request protection.

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