Research Of The Location System Of The Weak Point Of The Stator Winding Insulation Of High Voltage Motor

In this paper, based on the characteristics of high voltage motor stator winding, in view of the existing methods can only judge phase stator winding partial discharge quantity and cannot locate insulation weak points, design acoustic and electric composite sensor and data acquisition system, with the existing pulse current method to determine the location of electrical partial discharge, so as to realize the pulse current method phase, acoustic and electric composite sensor positioning of the objective. To this end, this paper mainly carries on the following three aspects of research:(1) The principle of acoustic electric combined positioning and the design of sensor. In view of the physical and chemical phenomena under the partial discharge of the stator winding of the high voltage motor, a method is proposed to locate the weak point of the insulation by using ultrasonic signals and electromagnetic signals. According to the acoustic electric combined positioning method, design the electromagnetic sensor and select the ultrasonic sensor.(2) The design of hardware circuit, contains the front electro acoustic signal conditioning circuit and data acquisition circuit. Some signals which collected by acoustoelectric compound sensor, contain the PD signal and all kinds of noise interference, so signal processing circuit is designed in this paper. Signal processing circuit mainly includes impedance matching, integral operation, preamplifier, band-pass filter and other circuit. The dual core shielded cable as a transmission line between sensor and signal processing circuit, this design can suppress common mode interference signal very well. The data acquisition system is mainly based on the TMS320F2812. Because the signal acquisition and conversion module of 2812 can only input DC signal, so the acoustic electric signal processed precision rectifier. Then, according to the demand, the amplified circuit is used to amplify the signal. The input protection circuit should be added before ADC module, to prevent excessive signal damaging ADC module. Because the ADC module of DSP2812 is not accurate enough, it is necessary to correct the ADC module. By using the calibration parameters, the data should be collected by one by one. Finally, the corrected data is stored in an external RAM.(3)The software design, including the design of the CCS programming and upper monitor. In order to display the collected data in real time, I design the waveform display by Lab VIEW inPC, which communicate with the hardware circuit by the USB virtual serial port. By reading the data stored in the chip, the waveform display can show the data in PC one by one.