Study Of A New Type Of Fault Locator For The High Voltage Transmission Line

At present,all the existing fault location methods for HV transmission lines can be classified into two main types: travelling waves location and fault analytical location. The merit of travelling waves location is its high precision, but it has dead line if the fault location is close to the line terminal or the fault occurs at the time close to zero point of current. Because affected by the type of lines, fault resistance and two sides systems,fault analytical location has lower precision, but it has no dead line and is more better accurate if the fault location is close to the line terminal. It has been proved by theories and practices that travelling waves location and fault analytical location methods have complementarities, and to use only one cannot meet the system requirements.In this article, a new design scheme of the fault locator for HV transmission lines is presented, which can realize both travelling waves location and fault analytical location. By using high-speed data acquisitioning unit designed specially to capture travelling waves of transient current, using Global Positioning System (GPS) to supply high precise time tagging for both ends, using wavelet transform theories to identify the head of the travelling waves, the fault locator can realize high precise double-ended travelling waves location. At the same time, using two-terminal voltages and currents sampled by the medium-speed sampling and processing unit synchronized by the Pulse Per Second (1PPS) of GPS, the fault locator can realize accurate double-ended steady-state location.Using the high-performance Digital Signal Processor (DSP) as CPU, the author designs the medium-speed sampling and processing unit of the fault locator. On the one hand, this unit can sample voltages and currents of the line synchronously; on the other hand, this unit can start the fault locator up and select the fault lines when faults occur. With ISA interface, this unit can make up of fore- and back-ground structure with industrial PC, and the fault locator can inspect multi-lines by adding more of it.In addition, the double-ended location is based on double-ended communication. The fault locators use MODEM to exchange data with each other remotely. In order to enable the fault locator to complete the whole procedure automatically, the author has written the communication programs...