Active voltage arc-extinction method applicable to single-phase earth fault of medium voltage distribution network

Abstract

The invention discloses an active voltage arc-extinction method applicable to a single-phase earth fault of a medium voltage distribution network, and relates to the technical field of fault self-recovery of a medium voltage distribution network. The active voltage arc-extinction includes the following steps: a. continuously measuring bus three-phase voltage, zero sequence voltage and each outlet three-phase current, and when a single-phase earth fault is detected, conducting fault phase selection; b. designating a threshold Ires.g of a fault phase current magnitude and a threshold Ures.g of a fault phase voltage magnitude of a fault feeder; c. measuring the voltage and current of the fault phase, comparing the fault phase current magnitude of the fault feeder with Ires.g. According to the invention, the method can effectively increase the arc extinction of a low-resistance earth fault, and compensate current at a fault point as much as possible while excess voltage is effectively controlled, and ensures that arc at the fault point can be reliably extinct. According to the invention, for non-linear resistance earth, the method is also effective simply by changing program codes in current active compensating apparatuses, and has higher values when applied to engineering.

Description

technical field [0001] The invention relates to an active voltage arc suppression method suitable for a single-phase ground fault in a medium-voltage distribution network, and belongs to the technical field of fault self-healing of the medium-voltage distribution network. Background technique [0002] In order to limit the current of the single-phase grounding fault point, the medium voltage distribution network in my country generally adopts the small current grounding operation mode (the neutral point is not grounded and the arc suppression coil is grounded). The operation mode in which the neutral point is grounded through the arc suppression coil is also called resonant grounding. When a single-phase ground fault occurs in the system, it can compensate the capacitance current of the system to ground, reduce the current at the fault point, and promote the fault arc extinguishing. However, with the continuous expansion of the distribution network scale and the extensive ap...

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Problems solved by technology

[0004] In view of the above problems, the technical problem to be solved by the present invention is to provide an active voltage arc suppression method suitable for single-phase ground faults in medium-voltage distribution networks; Self-healing; according to the magnitude of the fault phase voltage and the fault phase current of the fault feeder during the fault, the amplitude and phase of the fault phase voltage are controlled within a certain range, and the existing active voltage arc suppression is improved when the low-resistance grounding fault occurs. arc suppression performance

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