A single-phase arc flash overvoltage limiting device based on the principle of metal grounding

Abstract

A metal grounding principle-based single phase arc light overvoltage limiting device is disclosed and comprises a monitoring module and a limiting device, wherein the monitoring module comprises a performance evaluation unit, a network selecting unit and a network optimization unit, wherein the limiting device comprises a high voltage isolation switch BD, a primary harmonic resonance elimination device GDQ, an intelligent controller GDM, an auxiliary secondary winding-equipped voltage transformer PT, a high voltage current limiting fuse protector assembly FU, a high voltage vacuum contactor JZ capable of individual phase control and a three phase combined type overvoltage protection device GDB. The device can be used for switching off corresponding apparatuses according to user requirements, magnitude of currents is used as criteria, a plurality of locking functions can be fulfilled, and reliable power supply of a power grid system can be ensured.

Description

technical field [0001] The invention relates to the field of electric power technology, in particular to a single-phase arc overvoltage limiting device based on the principle of metal grounding. Background technique [0002] Most of the power grids below 35kV in my country adopt the neutral point indirect grounding operation mode. When a single-phase intermittent arc-flash ground fault occurs in the neutral point indirect grounding system, the arc is continuously extinguished and re-ignited for many times, resulting in the accumulation and redistribution of charges on the ground capacitance of the system, and the inductance of the non-fault phase- High-frequency oscillation overvoltage is caused on the capacitor circuit. [0003] High-amplitude overvoltage aggravates the cumulative damage of solid insulation such as cables. At the same time, arc-ground overvoltage will also cause PT or fuse to blow, and more seriously, it will cause the arrester to explode. [0004] To sol...

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Problems solved by technology

[0003] High-amplitude overvoltage aggravates the cumulative damage of solid insulation such as cables. At the same time, the arc-ground overvoltage will also cause PT or fuse to blow, and more seriously, it will cause the arrester to explode.

[0004] To solve the problem of arc grounding, the method of changing the neutral point grounding method of the system was adopted earlier, using small resistance grounding, sacrificing the reliability of power supply to solve the problem of arc grounding, and later developed to adopt the principle of arc suppression coil, using the different voltage and current characteristics of inductors and capacitors , the inductance current is used to compensate the capacitive current. Since the arc grounding is high-frequency, the arc suppression coil designed according to the power frequency cannot compensate the high-frequency current. On the contrary, the connection of the coil will cause many side effects, such as: inaccurate line selection , easy to generate resonance, transmit overvoltage, etc.

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