Computer-aided partial discharge amplitude distribution measurement system for large electrical machines diagnosis

The authors describe a distributed intelligent measurement system for partial discharge amplitude distribution (PDAD) detection for large rotating machinery, such as power generators. The equipment design is based on a modular adaptive technique, which allows the flexibility required for applications to different types of generators. The partial discharge acquisition and computing system is based on two main units. The remote unit is located close to the system to be tested and is designed to supervise the dynamic conditioning process as well as the acquisition and fast preprocessing of the probe signals. The second unit has no specific location and is linked with the first one by means of a fiber-optic data link. The second unit mainly consists of a PC (personal computer) having properly designed software tools to assist acquisition and perform real-time information analysis and diagnostics. This measurement system was used to perform tests on a nonloaded hydrogenerator equipped with a directional coupler. Experimental results are presented