Small-current grounding system fault transient traveling wave detection device and method

Abstract

The invention relates to a small-current grounding system fault transient traveling wave detection device and a method. The detection device comprises a power frequency starting element, a power frequency sampling unit, a high-speed sampling unit and a central processing unit, wherein the power frequency sampling unit is used for supplying a power frequency starting signal; the power frequency sampling unit is used for sampling a power frequency zero-sequence voltage fault component when receiving power frequency starting signal and transmitting the power frequency information to the high-speed sampling unit and the central processing unit when receiving a transient traveling wave starting signal; otherwise, transmitting the sampled power frequency zero-sequence voltage fault component to the central processing unit; the high-speed sampling unit is used for sampling a transient traveling wave current signal on each circuit, when the power frequency starting signal is received, a fault happens, conducting wavelet transformation for the current traveling wave on the corresponding circuit according to the power frequency zero-frequency voltage fault component and the transient traveling wave current signal and transmitting to the central processing unit; the central processing unit is used for receiving a calculation result of the high-speed sampling unit on each circuit and searching a fault circuit according to the result; and otherwise, searching for the fault circuit according to a stable fault component.

Description

technical field [0001] The invention relates to fault detection of a small current grounding system, in particular to a fault transient traveling wave detection device and method for a small current grounding system. Background technique [0002] At present, most of the neutral points of power distribution systems at home and abroad adopt non-effective grounding methods. Such power distribution systems are traditionally called small current grounding systems. The biggest advantage of this system is that when a single-phase ground fault occurs, the symmetry of the line voltage of the system will not be destroyed, and the system can continue to run for 1h~2h. Further expansion of the fault. [0003] However, if the ground fault in the small current grounding system exists for a long time, the fault arc may burn out the fault point, cause a short circuit fault, and cause the accident to expand. This is especially true for cable networks. Since the voltage of the non-fault li...

AI Technical Summary

Problems solved by technology

The strength of the injected signal of the injected signal method is limited by the capacity of the PT or the arc suppression coil. When the power of the injected signal is not large enough, the signal measured on the high-voltage side is weak, and it is difficult to accurately select the line; when the grounding resistance is large, the distributed capacitance on the line It will shunt the injected signal and cause interference to the line selection and fixed point; if there is an arc phenomenon at the grounding point, the injected signal will be discontinuous in the line and will destroy the signal characteristics, whether it is a cable line or an overhead line in the fixed point line. signals are not easy to identify

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