Power distribution network high-resistance grounding fault identification method based on real-time measurement of damping difference value of double voltage transformers

Abstract

The invention discloses a power distribution network fault identification method based on real-time measurement of damping rates of double voltage transformers. The method comprises the following steps: firstly, injecting a pilot-frequency constant-amplitude small current characteristic signal into a system through a three-phase voltage transformer of a power distribution network system, and measuring and calculating the equivalent damping rate of a power distribution network in a normal operation state according to a return signal detected by a three-phase no-load voltage transformer at the other end; and if the distribution network system has a grounding fault, calculating a damping rate difference coefficient of the distribution network by combining a characteristic signal returned in real time when the fault occurs and an equivalent damping rate under a normal condition, and realizing high-precision identification of the high-resistance grounding fault by comparing the difference coefficient with a difference threshold coefficient. Simulation results show that the method is wide in fault identification range and is not influenced by the asymmetry degree of the system, the double voltage transformers ingeniously eliminate the influence of leakage impedance and leakage reactance on measurement, and the problem that a traditional fault detection method is low in transition-resistant resistance capacity is effectively solved.

Description

technical field [0001] The invention relates to the technical field of ground fault identification of a distribution network, in particular to a high-resistance ground fault identification method of a distribution network based on real-time measurement of the damping difference of dual voltage transformers. Background technique [0002] The distribution network goes deep into the power terminal area, and the operating environment is complex and changeable, and high-resistance ground faults are prone to occur. As a prerequisite for fault handling, fault detection is of great significance to ensure the reliability and safety of power supply in the distribution network. The traditional distribution network mainly detects the zero-sequence voltage amplitude of the neutral point for fault identification, but when a high-resistance ground fault occurs, the zero-sequence voltage offset of the neutral point is small, and this method is difficult to carry out effective fault identific...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the current technical problem of inaccurate ground fault detection, this invention proposes an active detection method for high-resistance ground fault identification in distribution networks based on real-time measurement of dual voltage transformer damping. This method changes fault detection from passive detection to For active detection, it effectively makes up for these defects

Images