Compensation network single-phase ground fault line selection device and method

Abstract

The invention relates to a compensation network single-phase ground fault line selection device and a compensation network single-phase grounding fault line selection method. The external end of the network is connected with a grounding switchable direct current detection source; an analog signal extraction device is connected to the network and is connected with a digital signal processor (DSP) through an analog / digital (A / D) conversion module; and the DSP is connected with a control computer, and an alarm display and is connected with the switchable direct current detection source. The device has the advantages that quintic components in a fault signal can be enhanced and are not influenced by parameter variation of the system when a single-phase grounding fault of the network occurs; a stable criterion is provided for the fault line selection; and moreover, by adoption of a wavelet technology with high signal processing capacity compared with the traditional Fourier transform, quintuple harmonics are extracted through reconfiguration, the disturbance variables and high order harmonic components in signals are filtered, and the signal to noise ratio is improved.

Description

technical field [0001] The invention relates to a line selection device and method for compensating power grid single-phase grounding fault. Background technique [0002] For a long time, many scholars at home and abroad have done a lot of research on the problem of single-phase ground fault line selection in small current grounded compensation grid systems, and have produced many theories, methods and devices for ground line selection. However, in actual use, due to certain limitations of these line selection principles and criteria, the accuracy of the line selection device is not high in practical applications. [0003] For example, the most widely used traditional fifth harmonic method, the signal used for the fault criterion is very weak, the accuracy rate of detection is already low, and after processing and calculation, the accuracy rate cannot be guaranteed at all. Especially in the grounding system through the arc suppressing coil, the steady-state current flowing ...

AI Technical Summary

Problems solved by technology

However, in actual use, due to the limitations of these line selection principles and criteria, the accuracy of the line selection device is not high in practical applications.

[0003] For example, the most widely used traditional fifth harmonic method, the signal used for the fault criterion is very weak, the accuracy rate of detection is already low, and after processing and calculation, the accuracy rate cannot be guaranteed at all

Especially in the grounding system through the arc suppression coil, the steady-state current flowing through the fault line is very weak, even smaller than the current of the sound line, coupled with the interference of environmental electromagnetic interference and high-order harmonics, coupled with the influence of line structure, parameters, The operating state has a great influence, so it is very unreliable to extract the fifth harmonic directly according to Fourier decomposition, and the fifth harmonic is often not detected

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