Grounding line selection method for resonant grounding system based on instantaneous impedance grounding method

Abstract

The invention relates to a grounding line selection method for a resonant grounding system based on a transient impedance grounding method. The main technical feature is that: when the zero sequence voltage of the system is greater than a protection setting value, whether an influence is a ferromagnetic resonance influence or not is judged, a grounding event is recorded if so, otherwise, groundingdata is continuously recorded, a transient algorithm is started, a faulty line is judged, and three lines with largest probabilities are outputted for auxiliary decision; if grounding is steady-stategrounding, a final line selection result is comprehensively outputted; whether a fault is an intermittent continuous grounding fault or not is judged, the transient algorithm is started if so, the transient waveform analysis is performed, and a first fault judgment result is outputted; and a grounding event is recorded if the fault is not the intermittent continuous grounding fault. According tothe method, the fault line selection requirements under various fault conditions can be effectively satisfied, the accuracy of line selection is high, the reliability is high, the fault processing time can be effectively reduced, the labor cost of fault processing is reduced, and the power supply reliability and power quality of the system are improved.

Description

technical field [0001] The invention belongs to the technical field of relay protection, in particular to a grounding line selection method for a resonance grounding system based on an instantaneous impedance grounding method. Background technique [0002] In the power system, the system below 35 kV generally adopts the arc suppressing coil grounding method to form a resonant grounding system. In this mode of operation, when a single-phase ground fault occurs in the line in the system, the arc suppression coil will compensate the capacitive current generated by the fault, and control the current passing through the fault point at a lower level to ensure that the system can operate with faults1 -2 hours. However, due to the compensation function of the arc suppression coil, the current changes little after the fault, which also brings difficulties to the fault line selection. [0003] At present, for the resonant grounding system, there are two commonly used fault line sele...

AI Technical Summary

Problems solved by technology

The above methods have limitations: the medium impedance method requires a stable grounding of the fault point, which is not suitable for single-point grounding that occurs frequently in a short period of time; the transient line selection method has high requirements for the collection of current mutations and is easily affected by environmental factors , for a stable single-phase fault grounding, its reliability is significantly lower than that of the medium impedance line selection method

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