Resonant grounding system fault line selection method based on reactive power flow directions

Abstract

The invention discloses a resonant grounding system fault line selection method based on reactive power transient component and power frequency component flow directions. When a zero sequence voltage amplitude value exceeds a definite value, a plurality of lines with maximum amplitude value are selected to serve as fault candidate lines, the fault candidate lines are sequentially subjected to consistency judgment of the transient component and power frequency component flow directions in a reactive power characteristic frequency band, the lines in which the flow directions of the reactive power transient component and power frequency component are inconsistent are fault lines, and when the flow directions of the reactive power transient component and power frequency component of all candidate lines are consistent, the bus grounding is faulty. The line selection method has the advantages that the transient state and power frequency information generated by a fault is simultaneously used, the method is not affected by polarity influence of a voltage transformer (TV) and a current transformer (TA), an extra device is not required, a living alone feature is achieved, and the applicability is high.

Description

technical field [0001] The invention relates to a small current grounding fault line selection method, which is suitable for a resonant grounding system and belongs to the field of distribution network fault detection. Background technique [0002] my country's 6-35kV medium-voltage distribution network mostly adopts the low-current grounding method. For the convenience of the city and the needs of special terrains, the scope of cable laying is getting wider and wider, so the system's capacitance current to the ground is increasing, which promotes the resonant grounding grid. proportion is increasing. [0003] When a single-phase ground fault occurs in the resonant grounding system, the inductance of the arc-suppression coil and the capacitance of the system to ground form a parallel resonant circuit, making the zero-sequence impedance of the system close to infinite, and the inductance current provided by the arc-suppression coil compensates the capacitive current of the sys...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the problem of incorrect selection of transient reactive power direction method caused by TV and TA polarity reverse connection in the existing resonant grounding system, and to provide a resonant grounding based on the flow direction of reactive power transient component and power frequency component System fault line selection method

Images