Capacitive grounding current distributed compensation method and device for medium-voltage power supply system

Abstract

The invention relates to a capacitive grounding current distributed compensation method for a medium-voltage power supply system, which belongs to the technical field of the capacitive grounding current compensation of a neutral non-grounding power supply system. In the method, capacitive grounding current distributed compensation transformers are arranged on lines, with relatively greater capacitive grounding currents, of the system in a distributed way, and only compensate the capacitive grounding currents of the corresponding lines, wherein the compensation capacity of each capacitive grounding current distributed compensation transformer is 1.1 times the capacitive grounding currents of the corresponding lines; and 40 to 60 percent of the capacitive grounding currents of the system is compensated by the capacitive grounding current distributed compensation of the whole power grid, and the other is comprehensively compensated by arc extinguishing devices of transformer substations. The capacitive grounding current distributed compensation method has the advantages that: the capacitive grounding current distributed compensation transformers are adopted, so arrangement is simple and maintenance is unnecessary; operation is simple and the capacitive grounding current is compensated in real time; and the power supply reliability of the power grid is radically improved.

Description

technical field [0001] The invention is applicable to the technical field of ground-to-ground capacitance current compensation in a neutral point ungrounded power supply system. Background technique [0002] In the neutral point ungrounded power supply system, when the capacitance current of the system to the ground increases, once the single-phase of the line is grounded, the arc will not be able to stop the arc itself, and the overvoltage generated by the arc re-ignition will endanger the insulation of the sound phase and cause a two-phase short circuit Faults, for single-phase grounding faults, it is not uncommon to cause distribution network accidents, causing insulation breakdown, bushing burst, two-phase short circuit, and even causing the switchgear of the substation to be "fired"; for this reason, the existing neutral point is not Grounded power supply systems usually use arc suppression coils for grounding at the neutral point, and compensate the capacitance current...

AI Technical Summary

Problems solved by technology

[0005] The invention provides a method and device for decentralized compensation of ground capacitive current in a medium-voltage power supply system to solve the problem of increasing the capacity of the arc-suppression coil in the neutral point ungrounded power supply system of the medium-voltage power supply system and the power supply of the neutral point ungrounded power grid For the problem of low reliability, the technical solution adopted by the present invention is: scatteredly install the distributed compensation ground capacitance current transformer on the line with relatively large ground capacitance current in the system, and the distributed compensation ground capacitance current transformer installed on each line Only compensate the ground-to-ground capacitance current of the line where the line is located, and the compensation capacity is 1.1 times the ground-to-ground capacitance current of the line where the line is located. The sum of the distributed compensation ground-to-ground capacitance current of the entire power grid is 40-60% of the system's ground-to-ground capacitance current, and the rest passes through the consumption of the substation. Arc device for comprehensive compensation

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