Transmission Line Fault Location Method Based On Fault Possibility Evaluation And Its Application In Fault Location System

It is very important to locate the fault position to expedite repairs and restoration of power, to guarantee the reliability of power supply and to improve the security, stability and economy of power system. Thus, many researchers pay a lot of attention on this issue.There are many factors can affect the fault location results, such as transient fault waveform distortion. When using different data window and fault location method to locate the fault position, the results are often not the same and the accuracy can’t be predicted. In addition, from the beginning to the end of the fault, each period of the waveform data contains the information of the fault position. With full use of the fault waveform, the reliability of the fault location results can be improved. Therefore, this dissertation researches on how to solve these problems mentioned above. The main work is as follows:1, Based on a variety of time-domain and frequency-domain fault location methods, a fault possibility evaluation index module is proposed to evaluate the fault possibility of each point on the transmission line.2, To make full use of the information in the fault waveform, this dissertation defines fault location method, data window and parameter of the transmission line as environmental variables of the fault possibility evaluation index. With repeated calculation of the fault possibility evaluation index by changing the environmental variables, each point gets a set of fault possibility value and using weighted method, a comprehensive evaluation value can be obtained. Select the point with highest evaluation value as the fault location point, a fault possibility comprehensive assessment method is proposed. By using ATP/EMTP, this fault location assessment method is tested under various fault conditions on a transmission line system model. Simulation results show that the proposed assessment method is correct and the fault location system is effective.3, Based on the common fault location algorithms and the comprehensive evaluation method of fault location, a fault location calculation module is constructed. Studying the access method of commercial ORACLE database a fault information monitoring module which can access the protection and information system is built. Studying COMTRADE format, a record file processing module has been developed.4, A fault location system based on B/S network architecture which can access the real protection and information system is developed. The system background includes fault location calculation module, fault information monitoring module and record file processing module. Using MYSQL, the fault record file database, transmission line parameters database and fault location knowledge database has been constructed. A WEB site to display fault location results and complete the human-computer interaction function has been constructed also.