Waveform separator apparatus and method for detecting leakage current in high voltage direct current power systems

Abstract

Determining direct current (DC) leakage current flowing through an insulating structure in a high voltage DC power system wherein the DC leakage current is a composite DC current having one or more high magnitude momentary spikes, and having a DC component and an alternating current (AC) component, wherein the AC component has a first rate of change, and wherein the DC component has a second rate of change less than the first, having (a) providing a waveform separator which is configured to receive the composite DC current flowing through the insulating structure and to separate the composite DC current into the corresponding DC component and AC component, and (i) receive at least one corresponding digital signal and the DC component, ii) analyze the at least one corresponding digital signal and the DC component, (iii) determine a resultant leakage current flowing through the insulating structure, (b) electrically connecting the waveform separator to the insulating structure, (c) separating, in the waveform separator, the composite DC current into the corresponding DC component and AC component, (d) receiving the AC component in at least one comparator and producing at least one corresponding digital signal, (e) counting one or more positive AC components in the at least one positive voltage comparator, (f) counting one or more negative AC components in the at least one negative voltage comparator, (g) producing at least one positive digital signal corresponding to the counted one or more positive components and a negative digital signal corresponding to the counted one or more negative components, (h) processing the positive digital signal and the negative digital signal, and the DC component, and determining a resultant leakage current flowing through the insulating structure.