Research On The Travelling-wave Fault Location System Based On Secondary Signal Of TV

EHV transmission lines take a lead role in power system, it can quickly, precisely find the fault location in the event of fault conditions, therefore, it not only can eliminate fault and recover electricity quickly, but also play an important role in the whole power system with safety, stabilization and economical run. Fault location based on fundamental components is easy to be affected by transition resistor, fault type, bus configuration and TA saturation, thus, its location accuracy is low. Nowadays, with the development of computer, correspondence and measure technology, transmission lines fault location based on traveling–wave develops widely and it is gradually practical. At present, current traveling-wave is the main practical method, however, it is necessary to measure current traveling-wave on each line of substation, which causes complicated location system, high requirements of hardware, correspondingly low project flexibility; in case of voltage traveling-wave location, it is only necessary to measure busbar voltage of substation, thus, fewer measuring signals , simplified fault location system, high flexibility are guaranteed, of course, it is more convenient to build the fault location system based on whole transmission power system. So the research of new fault location system based on the traveling-wave of the voltage will be significance in theory and expansive foreground in application.This paper sums up the actuality in research and in application, development background of transmission lines fault location. It analyse the characteristics and the problems of two fault location methods respectively based on traveling-wave and fundamental components. this paper presents a new idea of traveling-wave fault location based on Capacitor voltage transformer(CVT) secondary signal.The transformer of voltage(TV) is the key of the fault location based on the secondary signal of TV, especially, whether the transmit characteristic of Capacitor voltage transformer(CVT) can achieve the request of fault location.This paper bases on the high frequency of the traveling-wave, this paper emulates CVT high frequency model, Then build the transmission lines system model, emulates CVT transmission under different fault types and locations as well as other fault conditions, it sums up the general characteristics of CVT secondary transmission fault traveling-wave head. then reasoning the feasibility of fault location based on the secondary signal of CVT. This paper considering the research of the new fault location of the traveling-wave based on the secondary signal of TV. It detailedly introduces the main design principle of system, expatiates functional configuration characteristics of hardware and software system.According to the traveling-wave transmit characteristic of CVT, this paper presents a detection method of secondary wave head via wavelet transform, and choose a suitable wavelet function. Out of consideration of actual condition of project application, as to noise, this paper presents a self-adaptable threshold noise cancellation method; As to sampling fault data and interferer, it presents a judgement method of phase voltage and line voltage; As to difficult detection of wave speed, it presents a method of online measuring traveling-wave speed. Meanwhile, according to compare between emulate data and actual measuring data, these methods are proved effectively.As the important part of the research on the new fault location system, this paper accomplishes the design an development of the manage software., this paper introduces interface design project and functional realization method of transmission lines traveling-wave fault location software system.