Small-current grounding fault positioning method employing transient zero sequence current

Abstract

The invention relates to a small-current grounding fault positioning method employing a transient zero sequence current, and the method is especially used for a system of an instation no-selection-line device. The method comprises the steps: selecting at least three lines with the bigger transient zero sequence current through employing the transient zero sequence current amplitudes of all detection points at an outlet of a bus; determining that a jump point is a fault point through employing the characteristics that the monotone decreasing of amplitudes of the transient zero sequence currents of healthy lines and the monotone increasing of the amplitudes of the transient zero sequence currents of fault lines at first and then the monotone decreasing of the amplitudes of the transient zero sequence currents of fault lines, and determining that fault segment is a segment where the jump point is located. The method irons out the defects of the instation no-selection-line device, just employs the transient current signals, is wide in application range, is simple, and is easy to implement.

Description

technical field [0001] The invention relates to the field of electrical automation, in particular to a method for locating small current grounding faults using transient zero-sequence current. Background technique [0002] The distribution network has the characteristics of complex structure and scattered load, and the probability of transmission line failure is very high, especially the single-phase ground fault of the small current system. When a small current single-phase ground fault occurs in the system, the fault current is very small and the fault signal is weak, which makes fault detection, line selection and location very difficult. After a small current ground fault occurs on the line, the three-phase voltage is still symmetrical, so the system can run for 1 to 2 hours, or even longer, which can improve the reliability of power supply. However, it cannot run for a long time with faults. If the running time is too long, it will easily cause phase-to-phase short-cir...

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Problems solved by technology

However, it cannot run for a long time with a fault. If the operation time is too long, it will easily cause a phase-to-phase short circuit fault, and the damage to the power system will be more serious.

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