The Same Tower Circuit Transmission Line Fault Location Method

Along with our country economy scale expanding, and become the world's second largest economies, Domestic electricity shortage phenomenon intensified increasingly fierce and it lead to rapid growth in demand for power. Because EHV transmission lines always Take on the role of large capacity, long-distance transmission and networking tasks, so the reliability of the transmission of power becomes more and more important. With the growth of population, the cost of the transmission network construction becomes more and more higher. Therefore, how to increase the transmission capacity of transmission lines and reduce the electric power construction investment on the basis of reliability requirements become a research hotspot at home and abord. Multi-circuit transmission lines in the same tower meet the inevitable trend of transmission capacity and request of the occupation of land, so it Become the inevitable trend of development of high voltage power grid in China.Compared with the single line, the main features of multi-circuit transminssion lines is that the distance between the line is near. So it not only exists mutual parameters in each phase. but also exist mutual parameters in each line, compared with the single line, exists mutual parameters in each line.Compared with the single line, multi circuit transmission lines exists inter-line fault, so there are many various of fault type and fault location becomes more complex. The accuracy of fault location based on the amount of power frequency fault location algorithm is low because of system operating mode, the transition resistance, CT saturation, line distributed capacitance. EHV transmission lines produce a steady-state power frequency and transient high-frequency fault component failure when it occur fault. Transient signal contains more fault Information than power frequency signal. It contains fault location, fault direction and so on. So this paper research fault location by decoupling method of multi circuit transmission lines, particularity of circulation rate and theory of fault location. The main contents are as follows:1. The research object is double circuit transmission lines in the same tower, analyze the complexity and specificity and proposed the decoupling method of the double circuit transmission lines, discuss the double lines with vector and special characteristics of the vector and laid a solid foundation for the double-circuit transmission line fault location.2. Analyze the difficulty of the single-ended traveling wave fault location, the identification of Point of failure reflected wave isn't affected by healthy reflected wave in the circulation rate of double circuit. Sometimes, flashover position being different from lightning position, this paper proposed a method to solve this problem. Transmission line always occur transient fault, this paper discus the applicability of traveling wave fault location in transient fault. When it occur the same name-phase fault, the circulation rate of double circuit can't use any more, this paper use artificial neutral networkneutral network to establish a single-ended traveling wave fault location of the coarse side-fine side mode to identify fault point reflected wave.3. A time-domain algorithm for fault location on double circuit has been proposed. Compared with the single line, time-domain algorithm on double circuit doesn't need to collect voltage signal, and doesn't affected by CVT transfer characteristics. Most of the double circuit doesn't transposition, this paper use phase component to locate the fault.When transmission lines occurs arc fault, it can use arc transfer characteristics and least squares to locate the fault.4. On the basis of traveling wave and time-domain fault location method, analyze the decoupling of four circuit lines on the same tower in same voltage grade and different voltage grade. Verify the reliability of traveling wave fault location principle and time-domain algorithm on four circuit lines.