Development of PD on-line monitoring system for large turbine generators

The feature of partial discharge (PD) is an important aspect of generators' insulation. The paper introduces an automatic online PD monitoring system for large turbine generators. By using digital signal processor (DSP) sampling technology, the system can obtain a long duration PD signal with high sampling rate. Fast Fourier transform (FFT) analysis, finite impulse response (FIR) filter, Adaptive filter and Wavelet analysis have been used in data processing. DSP, high performance industry computer and multi-CPU server provide powerful ability for data processing. client/server structure and fiber distributed data interface (FDDI) network have been used in the system, so it can be expand to the distributing monitoring system for monitoring several generators in the same power plant simultaneously. Information of PD pulse can be kept in the database in server permanently; it can be used to follow the track of large generators aging. The system can recognize several typical PD in large turbine generator. Results from large turbine generators are given at the end of the paper.