Method and device for locating single-phase grounding fault of low-current grounding system

A single-phase ground fault and small current grounding technology, applied in the field of power systems, can solve the problems of not allowing the power grid to run for a long time with faults, not being widely used, and taking a long time, so as to shorten the troubleshooting time and improve the quality of power supply , the effect of high measurement accuracy

Inactive Publication Date: 2011-06-15
黄洪全
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  • Application Information

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This method needs to be manually searched along the line, which takes a long time, and the operation rule

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  • Method and device for locating single-phase grounding fault of low-current grounding system
  • Method and device for locating single-phase grounding fault of low-current grounding system
  • Method and device for locating single-phase grounding fault of low-current grounding system

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Embodiment Construction

[0019] figure 1 The working principle of the present invention is explained. Assuming that there is a ground fault in phase C, the different-frequency signal generator is connected to the ground phase C-phase, and a different-frequency sinusoidal current is injected into phase C. The current detection channel detects the current signal of the fault circuit and is amplified by filtering. And convert it into a digital quantity, and send it to the control operation part. The voltage detection channel performs similar processing on the loop voltage, and the control operation part performs Fourier transform on the current and voltage signals to obtain the complex impedance of the fault circuit at the frequency of the injected signal. Its imaginary part is the reactance value, and the reactance value is multiplied by a proportional constant to obtain the distance from the signal injection point to the fault point.

[0020] figure 2 is a structural schematic diagram of an embodimen...

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Abstract

The invention discloses a method and a device for locating a single-phase grounding fault of a low-current grounding system. When the low-current grounding system has the single-phase grounding fault, a signal with pilot frequency different from grid frequency is injected between a fault phase and the ground, the voltage and current of the pilot frequency signal are detected at a signal injection end, an imaginary part of complex impedance of a fault loop under the frequency, namely a reactance value is calculated, and the distance between a signal injection point and a fault point can be obtained by multiplying the reactance value by a proportional constant. The signal is only needed to be injected at one end of a power grid, and the fault distance is directly measured and calculated, so that the method is simple and practicable, has high measuring accuracy, and has great significance for shortening fault removal time and improving the power supply quality of the power grid.

Description

technical field [0001] The invention belongs to the field of electric power systems, and in particular relates to a method and device for measuring a distance of a single-phase ground fault point in a small current ground system. Background technique [0002] In my country's medium and low voltage power supply system, the neutral point of the transformer is not grounded or grounded through the arc suppression coil, which is commonly known as the small current grounding system. The system is located at the end of the entire power supply network, and the overhead line transmission method is generally used, which is widely distributed. Single-phase-to-earth faults occur when overhead insulators are damaged, aged, or contaminated. In order to avoid further expansion of the fault, the power station staff usually stops the power supply, finds the fault point, replaces the faulty part, and restores the power supply after troubleshooting. Accurately calculating the distance of the...

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Application Information

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IPC IPC(8): G01R31/08
Inventor 黄洪全
Owner 黄洪全
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