Abstract
With the increase of generator running time, the probability of generator rotor problems increases constantly. In this paper, a generator is taken as an example. During maintenance, the generator is found to have the evidence of turn-to-turn short circuit of rotor windings by the repetitive surge oscilloscope method, which is verified by the AC impedance power loss test of the rotor winding. The position of turn-to-turn short circuit is determined by the inter-pole voltage method and the coil voltage method. The accuracy of the test method is further verified by the generator rotor’s return repair.
Highlights
In the background of electricity market developing slowly and frequent participation of thermal power generating units in peak-adjusting depth, the annual start and stop times of generating units are increasing year by year, and the failure rate of generator rotor is on the rise, among which turn-to-turn short circuit accounts for the largest proportion
There are some main reasons for rotor turn short circuit fault: 1The number of thermal expansion of the windings increases, and the displacement between turns increases; 2 The rotor end windings are almost exposed, oil and foreign matter are easy to invade, uneven cooling resulting in deformation of the windingss; 3 Fixed end loose, the process of starting and stopping by centrifugal force, thermal stress caused by the action of insulation damage
This paper finds out that there is a sign of turn-toturn short circuit in the rotor windings by using repeat pulse method
Summary
In the background of electricity market developing slowly and frequent participation of thermal power generating units in peak-adjusting depth, the annual start and stop times of generating units are increasing year by year, and the failure rate of generator rotor is on the rise, among which turn-to-turn short circuit accounts for the largest proportion. If the generator runs for a long time in the state of turn-to-turn short circuit fault, the excitation current of the rotor will significantly increase. There are some main reasons for rotor turn short circuit fault: 1The number of thermal expansion of the windings increases, and the displacement between turns increases; 2 The rotor end windings are almost exposed, oil and foreign matter are easy to invade, uneven cooling resulting in deformation of the windingss; 3 Fixed end loose, the process of starting and stopping by centrifugal force, thermal stress caused by the action of insulation damage. The shutdown treatment period is short and the effect is pretty good
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