Finding method of multi-branch-circuit power generator stator winding grounded short circuit point

Abstract

The invention provides a finding method of a multi-branch-circuit power generator stator winding grounded short circuit point. The method particularly comprises the following steps: (1) finding out the fault phase by utilizing megameter split-phase shaking insulation; (2) adding a direct-current power supply among m neutral points, setting a voltage meter at the outlets of each neutral point and a power generator over the ground, and finding out the fault neutral point through comparing the numerical reading of the voltage meter; (3) applying an alternating-current power supply over the ground at the fault neutral point, setting current meters on all branch circuits connected with the fault neutral point, and finding out the fault branches through comparing the numerical reading of the current meters; and (4) applying alternating-current power supplies over the ground at the fault neutral point, measuring all wire bars on the fault branch circuits one by one by adopting a tong-type current meter, wherein the measured current of the wire bars is suddenly changed to be zero, the wire bars are fault wire bars. The finding method of the multi-branch-circuit power generator stator winding grounded short circuit point provided by the invention is time-saving and labor-saving, the complex operation and welding quality hazard which are brought after each branch circuit is opened are prevented, and references are provided for the other same type of multi-branch-circuit large power generator stator winding grounded fault investigation.

Description

technical field [0001] The invention relates to the maintenance field of generators, in particular to a method for finding grounding short-circuit points of stator windings of multi-branch generators. Background technique [0002] The grounding fault of the generator stator winding is a common and highly destructive fault, which will have a series of serious effects on the safe operation of the power plant generator and even the power grid. [0003] The present invention takes the Pubugou Hydroelectric Power Plant as an example, which consists of two power stations, Pubugou Power Station and Shenxigou Power Station. There are 10 generators in the two stations with a total installed capacity of 4260MW, among which: Pubugou Power Station has 6 installed capacity, totaling 3600MW; Shenxigou Power Station has installed capacity 4, totaling 660MW. The model of Pubugou No. 1 generator is SF600-48 / 14200, the rated voltage is 20000V, the rated capacity is 667MVA, the rated current ...

AI Technical Summary

Problems solved by technology

Since the 6 branches are confluence tubes welded to 2 integral copper plates, it takes a lot of time to iron out and restore later.

At the same time, due to the narrow space, it will bring disadvantages to the future welding recovery work, and there may be hidden dangers in welding quality

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