Earth fault phase identification method based on injection method

Abstract

The invention disclose an earth fault phase identification method based on an injection method. The earth fault phase identification method includes the steps of (1) determining a phase angle Theta nor and the compensation state of an arc extinguishing coil based on system parameters (system total capacitance and damping ratio); (2) injecting current to a neutral point to obtain a compensated neutral point voltage when a power grid has single-phase earth faults; (3) determining the range of the compensated neutral point voltage phase angle a varying along the fault resistance when each phase has the single earth faults; and (4) determining the phase angle a falling into which variation range in step (3) based on the measured phase angle a of the neutral point voltage to determine whether the phase corresponding to the variation range has earth faults or not. The earth fault phase identification method based on the injection method can effectively realize the system earth fault phase identification, particularly realize the high-resistance earth fault phase identification, thereby overcoming the limitation of a conventional fault phase identification method and having better application prospects.

Description

technical field [0001] The invention relates to the technical field of fault phase identification of a power system grid, in particular to a ground fault phase identification method based on an injection method. Background technique [0002] my country's medium-voltage distribution network is mainly based on the small current grounding method. The commonly used methods are the neutral point grounding method through the arc suppression coil and the neutral point non-grounding method. With the rapid development of the distribution network system, the system single-phase The frequency of ground faults is increasing. In reality, due to the unbalance of the three phase-to-ground parameters of the power grid, it brings certain difficulties to the identification of the ground phase of the power grid, especially when a high-resistance ground fault occurs, the traditional ground phase identification is not applicable. Contents of the invention [0003] The object of the...

AI Technical Summary

Problems solved by technology

In reality, due to the unbalance of the three phase-to-ground parameters of the power grid, this brings certain difficulties to the identification of the ground phase of the power grid, especially when a high-resistance ground fault occurs, the traditional ground phase identification is not applicable

Images