Fault Traveling Wave Signal Detection Method Based On The Theory Of SR-HHT

The demand of the reliability of the electric power supply is increasing in modern society, it's more and more important that problems can be timely detected and rapidly diagnosed and corresponding protective measures can be made. Traveling wave protection has following advantages such as quick acting time and not affected by transition resistance and system oscillations. It has become a hot topic in the field of domestic and international protection. However, high frequency noise is often associated with travelling wave transmission, and the travelling wave signal can't be detected effectively. Therefore, the paper studied the fault traveling wave signal detection technique and proposed a detection method applied to background noise.Traveling wave signal detection method is divided into two parts: One part is signal extraction, the other part is the software analysis of extracted signals. First, electromagnetic interference during hardware extraction and noise interference during software analysis has been studied. The paper designed a simple structured new type PCB travelling wave sensor based on the analysis of Rogowski coil operating characteristic. It also has advantages such as good transfer characteristics and strong anti-electromagnetic interference ability in the matter of detecting the travelling wave in fault location. Moreover, under the strong noise, the paper raises a method to detect the travelling wave in fault location based on a theory of SR-HHT. It innovatively combined stochastic resonance theory(SR) and Hilbert-Huang Transform(HHT). The traveling wave signal can be effectively detected under background noise. The procedure is that the traveling wave signal is pretreated by SR theory first to get the traveling wave signal after the effective noise filtering, and then the signal was analyzed by HHT, and ultimately realized accurate detection of traveling wave signal fault feature information; Then, the paper made a simulation comparative analysis of SR-HHT method and wavelet transform and HHT transform, the results showed that SR-HHT method under the noise background has superiority in detecting the fault traveling wave signal. Finally, simulation analysis was made by EMTP-ATP electromagnetic transient simulation software for a 10 kV distribution line and fully proved that the method can effectively get mutation information of fault traveling wave under noise background and get accurate fault location.The method studied in this papers can accurately detect the traveling wave signal failure occurred under noise background and ensure precision and reliability of distance protection of transmission wave, and effectively shorten the recovery time and guaranteed the security and stable operation of power system.