Suppression of External Electrical Interference
Greg C. Stone, Andrea Cavallini, Glenn Behrmann, Claudio Angelo Serafino · 2023
External electrical interference (also known as electromagnetic interference – “EMI,” or radiofrequency interference – “RFI”) is encountered with most offline and all online partial discharge (PD) measurements. Knowledge of the typical types of external interference encountered when performing electrical PD measurements is essential, since it affects the quality of any PD measurement and the probability of a false positive indication of high PD. The interference environment and its impact on the PD results tend to be different between offline tests performed in a factory or laboratory, and either offline or online tests performed in the substation or plant. This chapter discusses these differences in general. It also discusses methods that have been used to suppress the influence of interference. Many of these methods can be used with offline tests in the factory/laboratory, or with off- and online tests at the substation/plant site.