Arc suppression coil grounding system single-phase grounding line selection method

Abstract

The invention provides an arc suppression coil grounding system single-phase grounding line selection method. The method comprises a step of collecting bus three-phase voltage, bus zero sequence voltage and branch circuit zero sequence current of different times, a step of calculating the fundamental component instantaneous value u'0(t) of the bus zero sequence voltage according to the bus zero sequence voltage, and judging a phase with a fault according to the amplitudes of the bus three-phase voltage of different times and the fundamental component instantaneous value u'0(t), a step of calculating zero sequence current fundamental component instantaneous amplitude values I0M,x of different times and different positions of a branch circuit of a phase with the fault, and calculating the zero sequence current fundamental component instantaneous amplitude values I'0M, x of the branch circuit after the arc suppression coil compensation effect is completed, and judging whether the branch circuit has a grounding fault according to the zero sequence current instantaneous amplitudes before and after arc suppression coil compensation. A line with an arc suppression coil single-phase grounding fault can be accurately selected without the influences of a field and the polarity of a zero sequence current transformer, the accurate of line selection is effectively improved, the group judgment is not needed, and a line selection process is greatly simplified.

Description

technical field [0001] The invention relates to a grounding fault line selection method of a power system, in particular to a single-phase grounding line selection method for an arc suppressing coil grounding system. Background technique [0002] In the power grid, if the capacitive current of a single-phase ground fault exceeds 10A and is less than 100A-150A, the distribution network should adopt the neutral point grounding method through the arc suppression coil. For the arc suppression coil grounding system, when a single-phase ground fault occurs, due to The inductance current of the arc suppression coil compensates the single-phase grounding capacitive current, so that the fault characteristics of the single-phase grounding fault are not obvious, which makes it difficult to select the faulty line, that is, it is difficult to select the grounding fault line. [0003] In the prior art, some methods suitable for single-phase ground fault line selection in the arc suppressi...

AI Technical Summary

Problems solved by technology

[0002] In the power grid, if the capacitive current of a single-phase ground fault exceeds 10A and is less than 100A-150A, the distribution network should adopt the neutral point grounding method through the arc suppression coil. For the arc suppression coil grounding system, when a single-phase ground fault occurs, due to The inductance current of the arc suppressing coil compensates the single-phase grounding capacitive current, so that the fault characteristics of the single-phase grounding fault are not obvious, which makes it difficult to select the faulty line, that is, it is difficult to select the grounding fault line

[0003] In the prior art, some methods suitable for single-phase ground fault line selection in the arc suppressing coil grounding system have been proposed, such as: waveform recognition method based on grounding instantaneous current and voltage transient information, instantaneous phase method, traveling wave recognition method, etc. These methods are susceptible to on-site interference, which makes the accuracy of single-phase ground fault line selection low, and the existing methods need to make group ratio judgments on all lines to find the single-phase ground fault line with the most obvious fault characteristics. The algorithm process is complicated, and what is more serious is that the correct judgment of these methods depends on the correct polarity of the on-site zero-sequence current transformer. cause the final judgment to be wrong

Images