Arc extinguishing cabinet and low current grounding system

Abstract

The invention discloses an arc extinguishing cabinet and a low current grounding system. The arc extinguishing cabinet is provided with a switching device and a low current grounding line selection device. The low current grounding line selection device is used for performing insulating monitoring and sampling of the three-phase voltage collected by a first voltage transformer group through a first input end and sampling the zero sequence current of a total incoming line cabinet through a second input end; and determining the fault phase and the fault type and controlling the switching deviceto switch the resistive load on the branch corresponding to the fault according to the voltage exceeding the first preset value and/or the zero sequence current exceeding the second preset value whenany one of the three-phase voltages exceeds the first preset value and/or the zero sequence current exceeds the second preset value so that the resistive load is switched on the the branch corresponding to the fault when the single-phase grounding fault occurs, the grounding current becomes resistive-capacitive grounding current, the amplitude of the power grid overvoltage can be suppressed and the purpose of suppressing the arc discharge generated by the single-phase grounding fault point and ensuring the safe and stable operation of the power system.

Description

technical field [0001] The present application relates to the technical field of power equipment, and more specifically, to an arc suppression cabinet and a small current grounding system. Background technique [0002] At present, in my country's 10kV and other medium-voltage distribution networks, in order to improve the power supply reliability of the power system, most distribution networks are small-current grounding systems. Impedance grounded three-phase system, also known as neutral point indirect grounding system. When a ground fault occurs in a certain phase, since a short circuit cannot be formed, the ground fault current is often much smaller than the load current, so this system is called "small current grounding system". [0003] In the low-current grounding system, when a single-phase reliable grounding fault occurs on the high-voltage side, only the fault phase voltage on the high-voltage side is 0V, and a lower induced voltage will be generated on the phase l...

AI Technical Summary

Problems solved by technology

And in the grounding wire, nearly 3 times the relative ground capacitance current during normal operation is generated, and the resulting ampere force (ampere force F=BILsinθ) makes the wire swing from side to side and is accompanied by intermittent arc discharge, causing damage to the surrounding people and equipment. If it lasts for a long time, it will cause resonance in the power system, causing safety accidents such as burning of power equipment and expanding power outages

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