Abstract: In order to realize the voltage test and partial discharge (PD) synchronous test of power cable, a two-sensor detection technology of partial discharge for cable under variable frequency series resonance is proposed. and the technology was verified in the laboratory. Firstly, based on the signal propagation characteristics of the partial discharge of the cable, a high frequency current transformer (HFCT) is used to detect the pulse signals (including interference signals and PD signals) flowing through the cable ground line as the main signal, and the ultra high frequency (UHF) use to detect the pulse interference signal generated by the variable frequency resonant sets as a reference signal. Secondly, the time domain sliding energy search method based on the threshold window is used to perform pulse extraction on the two signals. According to the characteristics of the overlapping of the interference signals in HFCT signal and the UHF signal in the time domain, the intersection discriminant algorithm is used to separate and identify PD signals in the HFCT signals. Finally, a Phase Resolved Partial Discharge (PRPD) spectrum is constructed to determine the type of the PD. The result in laboratory show that the method can realize the separation and identification of PD signals under strong interference generated by the variable frequency resonant sets. This method is feasible to synchronous test of power cable variable frequency resonance and PD test, which has certain guiding significance for practical engineering.