Maximum line selection coefficient principle based single-phase earth fault line selection method for power distribution network

Abstract

The invention discloses a maximum line selection coefficient principle based a single-phase earth fault line selection method for a power distribution network. The method comprises the steps of measuring a zero-sequence voltage of a bus and zero-sequence currents of all feeder lines of the power distribution network when the single-phase earth fault of the feeder line of the power distribution network occurs; switching a parallel resistor with parameters of an arc suppression coil unchanged, and measuring the zero-sequence voltage of the bus and zero-sequence currents of all feeder lines of the power distribution network again; and calculating line selection coefficients of all feeder lines to conduct fault line selection according to the maximum line selection coefficient principle corresponding to the fault feeder line. According to the method, the line selection principle is simple, line selection results are not affected by factors such as feeder line types, fault positions, line parameters, transition resistors, earth fault types and line lengths, the requirements for the reliability of hardware and algorithms are low, and the method is suitable for complex operation environments of the power distribution network and good in practicability.

Description

Technical field [0001] The invention relates to the technical field of fault line selection for power system distribution networks, in particular to a single-phase grounding fault line selection method for distribution networks based on the principle of maximum line selection coefficient. Background technique [0002] After the single-phase ground fault of the distribution network feeder, due to the compensation effect of the inductive current provided by the arc suppression coil, the zero-sequence current flowing through the faulted feeder is small, and the fault characteristics are not obvious, resulting in a large number of faulty feeders in the distribution network. difficult. The current feeder methods of distribution network are mainly divided into steady state method and transient state method. The steady-state method mainly uses the steady-state fundamental frequency or the harmonic electrical signals generated by the single-phase grounding of the distribution network fe...

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Problems solved by technology

The steady-state method mainly uses the steady-state fundamental frequency or harmonic electrical signals generated by the single-phase grounding of the distribution network feeder to complete the fault line selection function. This method often fails in line selection and cannot meet the practical needs of the site

The steady-state method is based on the fact that the transient component of the fault zero-sequence current is much larger than the steady-state value, and uses the transient zero-mode voltage and current in a certain selected frequency band to complete the function of fault line selection. The line selection accuracy is high, but the transient state The method has too high requirements on the reliability of hardware and algorithms, and cannot adapt to the complex operating environment of the distribution network, and cannot adapt to the practical needs of the site.

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