Single-phase earth fault positioning device for electrical power distribution network

Abstract

The invention disclose a new positioning method of a distribution network single-phase earth fault, which is applicable to a 3-60 kV neutral point ineffective earth grid. The principle of the positioning method is that: firstly, a high-voltage DC signal is poured into a circuit starting end and the DC signal is detected along the circuit so as to determine a fault area; then a high-voltage AC signal is poured into the circuit starting end, and the AC signal is detected along the circuit so as to determine the position of a fault point. A positioning device developed on the basis of the invention consists of two parts: a high-voltage signal source and a signal detector, wherein, the high-voltage signal source consists of a voltage inverter, a constant flow source, a transformer and a rectifier bridge and is used for pouring a high-voltage DC signal and a high-voltage AC signal; the signal detector comprises a DC detector and an AC detector, wherein, the DC detector consists of a Hall DC detector, a Bluetooth wireless sender and a Bluetooth wireless receiver and is used for measuring the DC signal; while the AC detector consists of an AC electromagnetic field inductor and a signal processing and display segment and is used for measuring the AC signal. The method and the device have mature technique and high reliability.

Description

technical field [0001] The invention belongs to electric power technology and equipment, which is suitable for 3-60kV neutral point non-effectively grounded power grids and can accurately locate single-phase ground faults. Background technique [0002] The 3-60kV distribution network in my country widely adopts the non-effective neutral point grounding method, also known as the small current grounding system, and most of the faults in the small current grounding system are single-phase grounding faults. When a single-phase ground fault occurs, the ground current is very small, and it can continue to run for 1 to 2 hours under the fault condition, but the fault point must be found as soon as possible, which raises the problem of fault location. [0003] The problem of single-phase ground fault location in distribution network has not been well solved for a long time. Manual line inspection not only consumes a lot of manpower and material resources, but also prolongs the power...

AI Technical Summary

Problems solved by technology

When a single-phase ground fault occurs, the ground current is very small, and it can continue to run for 1 to 2 hours under the fault condition, but the fault point must be found as soon as possible, which raises the problem of fault location

[0003] The problem of single-phase ground fault location in distribution network has not been well solved for a long time. Manual line inspection not only consumes a lot of manpower and material resources, but also prolongs the power outage time, affecting the safety of power supply

Some literature proposes to inject a high-frequency signal from the PT, and detect the signal along the line to determine the fault location, but because the distributed capacitance of the line forms a path for the high-frequency signal, the location is not accurate when it is grounded through a resistor

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