Single-phase earth fault line selection method of power distribution network earthing system

Abstract

The invention relates to a single-phase earth fault line selection method of a 10kV power distribution network earthing system. When the ratio between the inductance impedance value of an arc suppression coil and the impedance value of a harmonic elimination resistor is within some ratio range, and a single-phase earth fault occurs in the 10kV power distribution network earthing system, the difference between the zero-sequence voltage and the zero-sequence current of a fault outgoing line will be smaller than a preset value, and a protection device outputs a fault indication signal and an outgoing line switch actuating signal when the conditions are satisfied. The single-phase earth fault line selection method of the 10kV power distribution network earthing system has the advantages that parameter characteristic values on an arc suppression coil loop of the10kV power distribution network earthing system are adopted to be combined with the zero-sequence voltage and the zero-sequence current of the 10kV power distribution network earthing system, the changes of a phase angle cannot be easily influenced by factors such as operation conditions of the10kV power distribution network earthing system, criterion output is stable, and accuracy of judgment is high. The single-phase earth fault line selection method of the 10kV power distribution network earthing system can rapidly achieve fault location, can greatly improve the degree of automation of a power distribution network, can greatly reduce the time of a blackout of a user, reduces loss caused by the blackout, overcomes the defects existing in a small-current earthing operation mode, and has good social benefit and economic benefit.

Description

technical field [0001] The invention relates to a distribution network grounding system, in particular to a single-phase grounding fault line selection method for a 10kV distribution network via an arc suppression coil grounding system. Background technique [0002] At present, most of my country's distribution network adopts neutral point non-effectively grounded system (neutral point is not grounded or grounded through arc suppressing coil), and single-phase ground fault accounts for more than 80% of the total faults. At the same time, since there is no direct electrical connection between the ground and the neutral point or a reactor is connected in series, the short-circuit current is very small, and the protection device does not need to trip immediately, thereby improving the reliability of the system operation. [0003] However, due to the installed arc suppression coil, the single-phase grounding short-circuit current of the system is very small, and the voltage and c...

AI Technical Summary

Problems solved by technology

[0004] With the strengthening of the distribution network frame, the number of branch lines also increases, and it is very difficult to find out the location of the specific fault point with the traditional line inspection method

This not only consumes a lot of manpower and material resources, but also prolongs the power outage time and affects the reliability of power supply

Especially in severe cold winter, rainy and snowy weather, and difficult road conditions, the existing methods for finding fault points are very labor-intensive and difficult to meet the needs of current production

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