Generator stator winding single-phase earth fault position locating method

Abstract

The invention provides a generator stator winding single-phase earth fault position locating method. According to the method, firstly the single-phase earth fault is simulated on the generator end andcharacteristic parameters are calculated; then the fundamental voltage phasor of each winding bar and the fundamental voltage phasor of the tail end of each winding bar are calculated according to the stator winding connection diagram; then when the stator winding single-phase earth fault actually occurs, the three-phase fundamental voltage and the zero sequence voltage of the generator end are measured and calculated and the fault phase is judged; and supposing that the earth fault occurs on the tail end of each winding bar, the fundamental zero sequence voltage under the fault conditions iscalculated and compared with the fundamental zero sequence voltage under the condition of actual fault so as to judge the fault position. According to the method, the workload of actual parameter measurement is low, implementation is easy and the method is accurate.

Description

technical field [0001] The invention relates to relay protection, fault analysis and accident repair of a large synchronous generator in a power system, in particular to stator winding single-phase grounding protection of a large synchronous generator, fault analysis and accident repair technology for a stator winding single-phase ground fault. Background technique [0002] The single-phase grounding fault of the stator winding is a common fault of large synchronous generators in the power system. Since most large synchronous generators adopt the grounding method with the neutral point passing through the grounding transformer and load resistance, it is referred to as the high-resistance grounding method, or the arc-suppression coil grounding method, and the stator A large fault current will not be generated when the winding is single-phase to ground. However, the single-phase ground fault of the stator winding is often the first photo of the short-circuit fault of the stato...

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Problems solved by technology

The disadvantage of this method is that the formula is too simplified, omitting the T-type equivalent parameters of the grounding transformer will introduce calculation errors, especially when the difference between the grounding transformer and the ideal transformer is large, and the relevant T-type equivalent parameters cannot be ignored. There is some error in the result

[0007] In addition, theoretical analysis shows that when the ground fault occurs inside the generator stator winding, the fundamental wave voltage from the fault point to the neutral point and the fundamental wave voltage from the machine terminal to the neutral point, these two fundamental wave voltages are in phase There is a deviation in the above two methods, which does not take this factor into account, which will lead to inaccurate calculation results of the ground fault location when the internal ground fault occurs

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