Research On Fault Location Algorithm For Transmission Lines And Development Of Simulation Platform

Fault location for high voltage transmission lines can detect the fault point promptly and accurately, which can not only direct line patrol effectively, repair the damaged line and restore power, but discover the weak link and potential danger soon enough to improve operation reliability. Accurate fault location has significance for safe, stable and economic operation of power system.The post fault transient electrical quantities are affected by many factors, including fault type, inception angel, fault resistance, et al. Therefore, large volumes of fault data must be validated for a fault location method. Comprehensive and effective simulation and computation are costly and laborious and may result in errors if handled by manual work. Then the automatic simulation of multi-parameter varying and the efficient data processing have become an urgent need.The paper studies fault location methods of overhead transmission lines and hybrid transmission line composed of overhead transmission lines and buried cables, and develops a simulation-analysis platform. The main researches are as follows:(1) Give an overview of current fault location methods and compare their advantages and disadvantages, thus determine the single-ended methods as research direction, the combination of power frequency quantities and traveling wave as research approach, and the overhead lines and hybrid lines as research objectives. Give an overview of simulation and data process and then aim at developing a comprehensive platform for transient simulation and analysis.(2) A single-ended fault location algorithm for overhead transmission lines is proposed, based on the improved distributed-parameter method and variable time windows of traveling wave. First, according to the online estimation of the opposite terminal source impedance, the improved distributed-parameter method can be built, to compute the fault distance window. Then time windows of the reflected waves to be identified can be determined and they are variable to raise anti-jamming capability. At last, considering the wiring schemes, the exact fault location can be detected. Simulation results show that the method is not affected by wiring schemes, fault distance, fault resistance and system run mode, and demonstrate the high reliability and accuracy as well as the engineering application value of the proposed algorithm.(3) A single-ended fault location algorithm for hybrid transmission lines is proposed. First, the fault distance interval based single terminal power frequency electric quantity is computed, where the fault point location is primarily delimited, to enhance reliability and practicality of single-ended traveling wave method. Then the propagation law of the traveling wave within the delimited interval is analyzed, the fault location method is constructed, and the criterion to identify the fault occurred at the junction point and the criterion for the faulty section is put forward. Simulation results show that using the proposed method the accurate fault location results can be achieved, and there are no dead zones of fault location within the regions where the junction points of different conductor sections locate, therefore,the proposed method is suitable for hybrid transmission lines composed of multi-sections of different conductors.(4) An integrated automatic invocation method for ATP and Matlab is proposed based on their operation mechanism. On the basis of the method, a user-friendly simulation platform is developed, which can combine interactive setup, automatic simulation and data analysis.