Numerical Modelling and Pinpointing of Partial Discharges

In this chapter, we describe a spectral approach based on resonance that may be used to identify concurrent partial discharges in hydrogenerator coils. It is designed to offer a method of diagnosing the coil insulating material by accurately determining the positioning of various discharges. Numerical models of coil structures were created using the full-wave technique finite-difference time-domain (FDTD) to solve Maxwell’s equations. To quantitatively acquire the frequency spectrum for diagnosis, the transient voltages connected to partial discharges occurring at various points in the coil are calculated. Peaks in the spectrum are compared to analytically determined resonance frequencies. It is demonstrated that in almost 90% of the numerical experiments, precise predictions of the simultaneous discharge sites were made. The physical processes that enabled the method’s development were evaluated numerically and in laboratory.