The system architecture of selective frequency balance measurement for PD

PD (partial discharge) measurement is one of the most important parts in HV (high voltage) diagnostics. There are a lot of measuring methods of PD, such as impulse current, ultra-high frequency, super sonic method, and so on. The impulse current method is the earliest used in PD detection and is the most basic. Further the balance method is one of the impulse current methods. This method has higher inference rejected ability than others. But, the input circuits of traditional balanced PD measurement methods are composed of two parallel circuits of resistance and capacitance. There are many disadvantages with using this measuring circuit such as utilizing its application in HV and UHV (ultra-high voltage) measurements. A new selective frequency balance measurement theory for PD was put forward by the authors in 1988. The device, which was based on this theory, was also determined. Now, it will be verified in the HV field. The noise signal can be rejected more than 1000 times by this device. Furthermore, the device is very easy and cheap to produce using the new theory. The system structure of the selective frequency balance measurement circuit is dissertated. The design method is also explained and measuring results are illustrated