Biblio

At present, the acoustic emission (AE) method has the advantages of live measurement and easy fault location, so it is very suitable for insulation defect detection of power equipments such as GIS, etc. While the conventional AE detection system or instruments always can't give a right discrimination result, because them always work based on the reference voltage or phase information from an auxiliary 220V voltage signal source rather than the operation high voltage (HV) with the real phase information corresponding to the detected AE pulsed signals. So there is a random phase difference between the reference phase and operation phase. The discharge fingerprint formed by the detected AE pulsed signals with reference phase using the same processing process is compared to the discharge fingerprint database formed in the HV laboratory with the real phase information, therefore, the system may not be able to discriminate the discharge mode of the field measured data from GIS in substation operation. In this paper, in order to design and develop a general fast analysis algorithm model for PD acoustic detection system to make an assistant diagnosis, the pattern identification with phase compensation was designed and applied. The results show that the method is effective and useful to deatl with AE signals meased in operation situation.

The time delay of echo generated by the moving target simulator based on digital delay technique is discrete. So there are range and phase errors between the simulated target and real target, and the simulated target will move discontinuously due to the discrete time delay. In order to solve this problem and generate a continuously moving target, this paper uses signal processing technique to adjust the range and phase errors between the two targets. By adjusting the range gate, the time delay error is reduced to be smaller than sampling interval. According to the relationship between range and phase, the left error within one range bin can be removed equivalently by phase compensation. The simulation results show that by adjusting the range gate, the time delay errors are greatly reduced, and the left errors can be removed by phase compensation. In other words, a real continuously moving target is generated and the problem is solved.