Mitigation of the DC Offset by a Sub-Cycle Sample Method M-Class PMUs

The phasor estimation of the fault current signal in the presence of dc offset results in the significant error, which is not suitable for the power system monitoring. To reduce the phasor estimation error of the fault current in the presence of dc offset, primarily the dc offset needs to be mitigated. In this letter, a four-sample method, which requires four sub-cycle samples as the input and estimates the dc offset parameters present in the signal, is proposed. The test results show that the proposed method is simple and more accurate in mitigating the dc offset from the fault signal.