A New Method for Cable Monitor Wire Protection Based on Time-sharing Amplitude

Reason was analyzed that cable monitor wire protection was easy to make incorrect operation and failure action led by the stray interference signals. Full-wave Fourier Algorithm was deduced which was realized by filtering decaying dc component using table lookup. And on this basis, protection principle of time-sharing amplitude ac cable monitor wire with terminal resistance was proposed and proved in detail. Results showed that this method could effectively filter various stray currents, and especially it could absolutely filter interference signals with the same frequency as the additional ac signal. This method greatly improved the reliability and accuracy of the cable monitor wire protection proved by both theoretical analysis and simulation experiment, which had a significance to improve the reliability of underground power supply and reduce the breakdown.