Power distribution network single-phase earth fault sensing method based on transient state and steady state of phase current

Abstract

The invention discloses a power distribution network single-phase earth fault sensing method based on a transient state and a steady state of a phase current. The method comprises the steps: collecting the three-phase current of a power distribution network, synthesizing a zero-sequence current, calculating the amplitude of a fundamental wave, and obtaining a fault signal when a single-phase earth fault occurs, thereby obtaining a fault occurrence moment and a line fault component current; solving the fundamental component amplitude and the high-frequency component amplitude of the fault component current, and judging whether the quantitative relation between the fundamental component amplitude and the high-frequency component amplitude meets the fault sensing criterion or not; when the criterion is met, judging that the system has the grounding fault through the resistor, and obtaining a fault path positioning result by combining the steady-state characteristic of the fault component current with the variance; otherwise, judging that the system has an arc earth fault, and obtaining a sampling point at the fault occurrence moment and a three-phase current abrupt change direction by combining the transient characteristics of the fault component current with improved S transformation to obtain a fault path positioning result. The method is suitable for various single-phase earth fault types occurring in the power distribution network, and the operation reliability of the power distribution network is effectively improved.

Description

technical field [0001] The invention belongs to the technical field of electric power automation, and relates to a single-phase ground fault sensing method of a distribution network based on phase current transient steady state. Background technique [0002] As a bridge connecting the power system and users, the reliability of distribution network determines the quality and safety of power users. With the continuous progress of the economy and society, the distribution network presents a development trend of expanding scale and complex topological structure. The problem of single-phase ground fault in distribution network also has the characteristics of unclear fault characteristics and various fault situations. Single-phase ground fault The positioning problem has not been well solved and cannot meet the requirements of its economical and reliable operation. [0003] At present, the fault location technology of distribution network can be roughly divided into two types bas...

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Problems solved by technology

[0006] In order to solve the deficiencies in the prior art, this application provides a single-phase ground fault sensing method in distribution network based on phase current transient steady state, and detects single-phase ground fault in distribution network based on asymmetric signal between transient state and steady state. Sensing can solve the problem of complex fault conditions in the distribution network, meet the fault location requirements of multiple fault types and different neutral point grounding methods, and use the adaptive threshold to meet the requirements of high adaptability and weak dependence on communication

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