According to the problem that PD reference phase cannot be introduced into the applications using electronic transformer, this paper presents a discharge monitoring internal synchronization reference correction method based on the SV sampling: firstly, use the device’s internal timer to generate a virtual frequency cycle, which is the internal synchronization signal, then pre-calibrate the signals using the internal synchronization signal; secondly, amend the virtual frequency phase using the SV signals provided by the combined units, after this we can get accurate and reliable frequency phase reference. Whether conventional or electronic transformers, this scheme is very simple to implement and has the flexibility and popularity in engineering applications.
