Traveling Wave Fault Detection Based On Wavelet Transform Research

Fault phase selection component plays an important role in transmission protection. The traditional role of the fault phase selection components is to select the single fault phase when a single fault occurs and then trip the circuit breaker, Otherwise cut the three phase circuit breakers. So it is important to the auto-reclosing.With the widely application of digital micro-computer based protection devices in recent years, it is demanded that the fault phase selection components not only can select the fault phase when a single phase fault occurs, but also differentiate fault type when phase to phase faults occurs. The fault phase selection components not only can be applied to auto-reclosing, but also can be applied to the algorithm of the protection components' measuring devices ( such as distance components) and phase selection of fault location. Therefore, further research is required.The thesis analyzes the status of phase selection components, takes further research into the theory algorithm and application of various fault phase selection components, and studies the concepts of wavelet transform and its application in fault phase selection especially. The thesis clearly represented the relationship between fault characteristic of waveform and modulus maximum of wavelet transform: through utilizes limited numbers of modulus maximum of wavelet transform that each have a clear physical meaning with them, the fault characteristic of transit wavelet signal can be described completely and clearly.According to the application of wavelet transform in phase selection, the studied project analyzes several kinds of wavelet transform based phase selection methods, and points out their disadvantages, that is, the present methods take no consideration of the different speed and fading characteristic of different modules, thus can not determine the fault phase correctly. To...