Route selection method aiming at electric arc ground fault

Abstract

A wire selection method for arcing ground failure uses zero sequence voltage amplitude as a selection-judged starting signal. After the zero sequence voltage amplitude is more than a threshold value, a zero sequence voltage of each feeding wire being sampled, then 50Hz fundamental wave treatment is implemented to the sampling signals to obtain zero sequence transient state currents, further five to six feeding wires with maximum amplitude of zero sequence transient state current are selected as ''doubtful true'' failure feeding wires, from which a feeding wire with maximum amplitude is selected as a quantity ib(k) of standard feeding wire, and the ib(k) is multiplied with the zero sequence transient state currents of the other ''doubtful true'' feeding wires point by point separately, andan algebraic average of a period of time is calculated as failure predication quantity Wj. If only one Wj of the all Wj is negative, the corresponding feeding wire is the failure feeding wire; if allWj are negative, the standard feeding wire is the failure feeding wire; if all Wj are positive, the busbar is fault.

Description

technical field [0001] The invention relates to a small-current grounding line selection method for a power grid substation, which is suitable for any neutral-point grounded power grid and is particularly effective for arc grounding faults. The utility model belongs to the technical field of electric power automation. Background technique [0002] Both the experiment and the recorded wave data of the field grid prove that due to the complexity of single-phase ground faults, when some single-phase ground faults occur, there is only a steady state in the zero-sequence current of the feeder; some single-phase ground faults only have a transient state; Sometimes both. The laboratory physical simulation test also proves that under quite a lot of arc grounding conditions, the steady-state current in the fault current is very small or almost zero, while the transient current is very high, resulting in unsatisfactory line selection effects. The chances of rejection are high. Fiel...

AI Technical Summary

Problems solved by technology

However, due to the complex calculation and long calculation time, it is not suitable for developing line selection devices with single-chip microcomputers.

Images