DSP based on-line partial discharge monitoring system for high voltage power cable

In high voltage power cable system, partial discharge (PD) is a common phenomenon which reflects the degradation of insulation. When partial discharge happens inside the cable, leakage current will flow through the grounded conductor. To couple the partial discharge current, one feasible and effective method is placing a clamp-on high frequency current transformer around the grounded strap. In order to precisely monitor the insulation degradation, a digital signal processor (DSP) based partial discharge on-line monitoring system is developed and presented in this paper. The system mainly consists of PD sensor, pre-amplifier, front-end sample device and remote server center. The front-end device is the kernel part of the system, as it performs PD signals sampling and some essential digital signal processing such as noise filtering, pulse extraction and parameters statistics. Then, the derived characteristic parameters are sent to the remote server center by ethernet communication for further analysis. The field test and data analysis show the presented system is effective and helpful for power cable condition diagnosis.

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