Method and device for positioning and detecting single-phase grounding fault of power distribution grid

Abstract

The invention relates to a method and a device for positioning and detecting single-phase grounding fault of a power distribution grid. The device comprises a voltage transformer, an intelligent monitoring controller, a resistor switching device and a plurality of detection terminals, wherein the detection terminals are arranged on a power distribution line, one end of the voltage transformer is connected with a substation, the other end of the voltage transformer is connected with the intelligent monitoring controller, the other end of the intelligent monitoring controller is connected with the resistor switching device, one end of the resistor switching device is connected with the power distribution line, the other end of the resistor switching device is connected with the intelligent monitoring controller, the resistor switching device is grounded, and the detection terminals are arranged on different positions of the power distribution line. The method and the device have the advantages that the sensitivity of fault detection and positioning is improved, the detection range of grounding resistance is widened, and the area with single-phase grounding fault can be quickly and accurately positioned.

Description

technical field [0001] The invention relates to a detection and positioning technology for a distribution network ground fault, in particular to the technical field of a method and device for detecting and locating a single-phase ground fault in a distribution network. Background technique [0002] Single-phase ground fault is the main fault type in distribution network faults, which seriously affects the reliability of power supply. my country's distribution network is generally a small current grounding system, and the fault current is very small. If the system is grounded through the arc suppression coil, the fault characteristics will be less obvious, which makes the detection and location method relying on the magnitude and direction of the fault current invalid. [0003] In the detection and location method of single-phase ground fault in distribution network, the passive detection method depends on the transient characteristic quantity of the fault line, which is grea...

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Problems solved by technology

[0002] Single-phase ground fault is the main fault type in distribution network faults, which seriously affects the reliability of power supply

my country's distribution network is generally a small current grounding system, and the fault current is very small. If the system is grounded through the arc suppression coil, the fault characteristics will be less obvious, which makes the detection and location method relying on the magnitude and direction of the fault current invalid.

[0003] In the detection and location method of single-phase ground fault in distribution network, the passive detection method depends on the transient characteristic quantity of the fault line, which is greatly affected by the grid structure and operation mode of the system, and the accuracy of judging single-phase ground fault is not accurate. high

Although the active detection method is not affected by the system itself, the devices that inject characteristic signals into the system can only be connected to the neutral point of the grounding transformer in the substation, which greatly limits the scope of application of the active detection method; And the switching resistance value of the device that injects the characteristic signal is constant and non-adjustable, which makes the device only able to detect the fault condition that the grounding transition resistance is not high, otherwise the signal will be too weak to be detected, and the reliability will be low

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