Method capable of realizing low-current route selection and fault location

Abstract

The invention discloses a method capable of realizing low-current route selection and fault location and discloses a novel method capable of realizing single-phase grounding route selection and fault location. The method comprises the following steps: detecting the zero sequence voltage value of a system and the zero sequence current value of each branch line at the first time of the single-phase grounding fault; at the second time, changing the capacitance value or the inductance value of the whole power distribution network on the ground for a neutral point ungrounded system, changing the compensation degree of an arc suppression coil or changing the capacitance value or the inductance value of the whole power distribution network on the ground for an arc suppression coil grounding system, and detecting the zero sequence voltage value of the system and the zero sequence current value of each branch line at the second time after adjusting; and after determining the branch line of the single-phase grounding fault, uploading the detected zero sequence current value of the branch line, dividing the zero sequence voltage of the system by the detected zero sequence current value and judging to determine the position of the fault point. When the zero sequence current change of a voltage transformer on a bus influences the fault route selection and location, the zero sequence loop of the voltage transformer can be cut off, so that the detection precision is improved.

Description

technical field [0001] The invention relates to a method for small current connection line selection and fault location, in particular to a new method that can accurately realize single-phase ground line selection and fault location. Background technique [0002] At present, line selection for single-phase ground faults basically relies on comparison of zero-sequence currents. The scope of the fault line is very small, and its theoretical derivation has as many falsehoods as possible. For the neutral point ungrounded and small current grounded systems, the regulations stipulate that when a single-phase ground fault occurs, it is allowed to operate with the fault for two hours. Since the non-faulted phase voltage rises to the line voltage, long-term operation may cause insulation breakdown. Therefore, fast single-phase ground fault line selection and fault location have been our subjects for a long time, and have not been well resolved. The principle of the existing microco...

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Problems solved by technology

However, due to the limitations of technical means (universal problems) at that time, only the zero-sequence voltage of the system and the zero-sequence current value of each branch line could be detected, and only the capacitance value of the distribution network to the ground was adjusted; The zero-sequence current of the branch is not detected, and the change of the zero-sequence current of the branch will affect the detection accuracy of the faulty line selection. At the same time, there is no way to adjust the inductance value of the distribution network to the ground. In short, it has not achieved the point of excellence

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