Arc extinguishing method for single-phase earth fault of generator stator winding

Abstract

The invention discloses an arc extinguishing method for a single-phase earth fault of a generator stator winding. The method comprises the steps that if it is detected that the stator winding earth fault occurs, reference electromotive force is obtained and detected, namely, the reference electromotive force applies clamping voltage to enable neutral point voltage to be adjusted to be the clampingvoltage, then whether the voltage value of a stator fault coil is zero or not is judged, and if yes, the voltage of a clamped generator neutral point is selected as the optimal clamping voltage; if not, another reference electromotive force is selected for detection, wherein when the reference electromotive force is selected, turn-by-turn detection and analysis are carried out from the first turnof coil to the back on the same branch; and if the voltage of the fault position is not adjusted to 0 after the coils on one branch are searched and detected, the coil on the other branch in the samephase is analyzed until the voltage of the fault coil is adjusted to 0. According to the invention, the voltage at the fault coil can be adjusted to 0, and the problem of single-phase earth fault arcextinction is solved.

Description

technical field [0001] The invention belongs to the technical field of generators, and in particular relates to a single-phase ground fault arc suppression method for a stator winding of a generator. Background technique [0002] Stator winding single-phase ground fault is the most common type of fault in large generators, and it is often caused by insulation damage between the stator winding and the iron core. Large-scale generator sets at home and abroad generally adopt the neutral point non-effective grounding method to limit the single-phase ground fault current within the allowable range. The protection unit only sends signals without tripping. energy balance. However, the zero-sequence impedance of the neutral point non-effectively grounded system is large, the fault signal is weak, and it is very difficult to extinguish the arc of the single-phase ground fault of the stator winding. During the fault period, the repeated charging and discharging process of the capaci...

AI Technical Summary

Problems solved by technology

However, the existing measures cannot guarantee that the fault current is limited to below the 1A standard required by the regulations under high-resistance to low-resistance ground faults, and they are powerless to deal with intermittent arcing ground faults

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