Study Of Fault Diagnose Of Interturn Short Circuit In Generator Rotor Windings Based On Differential Coil Method

Generator as the important generation part of power system has a very close relationship with the safety and stability of power grid security and reliability of power supply. As the generator capacity continues to increase, the requirement of fault analysis technology has also been enhanced. Affected by machine, heat and electricity, rotating rotor of high speed is easy to have short circuit fault occurred in rotor interturns. So the diagnosis technology of generator interturn rotor short circuit fault is of great significance.In this paper, the change of air-gap magnetic field before and after short circuit fault occurred in generator rotor winding interturns is analyzed. Based on the monitoring principle of differential coil method, the feasibility of diagnosis before and after the fault using the concave shrinkage of the differential coil induction electric potential is discussed. Then the fault diagnosis and orientation by using wavelet analysis to collect signals of modulus maxima points is realized, and the air gap of coil and its differential signal under different working condition to analyze the field measured data is simulated by wavelet toolbox in Matlab, thus the feasibility of rotor fault monitoring by wavelet analysis method is verified. The device of short circuit fault diagnosis in generator rotor interturn characterized by differential coil induction electric potential quantity is initially explored. Also, the comprehensive design of short circuit fault monitoring system in generator rotor interturns and data acquisition system based on the DMM-32DX-AT and HC-GX-800is accomplished in this paper, in terms of analyzing the features of the hardware modules, the corresponding parameter and acquisition system hardware design and data acquisition card are introduced. At the same time the double cache data storage method which is to realize high speed data acquisition in the practical implementation is introduced and the data acquisition experiments in different sampling frequency are tested, the high speed data acquisition scheme is verified correctly in the card which made the foundation for subsequent perfect acquisition device.