Research And Implementation On Fault Location For Power Transmission Lines By Traveling Wave Method

With the development of power network interconnection, the scale of power system isextending, the demands for safety operation is increasingly higher. Because of wide distribution,complex terrain, erratic weather conditions and long-term exposure to natural environment, thetransmission lines get out of order unavoidably. At present, all the existing fault location methodsfor HV transmission lines can be classified into two main types: fault analytical location andtraveling wave fault location. Because affected by the type of lines, fault resistance and two sidessystems, fault analytical location has lower precision; traveling wave location is not widely usedbecause of difficultdetection for traveling wave head. The line inspection is used to find fault, butit is not good, because it wastes time, labor and resource, especially it is difficult to find fault pointfor instantaneous fault like flashover. Therefore, we need to find a method to find fault pointquickly and exactly.The paper systematically analyzes existing domestic and foreign methods for fault location oftransmission line, and in finally we adopted the traveling wave fault location based on single-endto realize fault location. The whole device of fault location is designed, which include the head oftraveling wave detection circuit, signal conditioning circuit and data acquisition block and so on.The paper systematically analyzes the propagation process of the transient traveling wave inthe power system. Wavelet transform was adopted to resolve the key problem in traveling wavefault location based on single-end—traveling wave head withdrawing. The experimental resultsshow that the precision of wave withdrew has been greatly improvedThe digital signal process technology is applied in the project. It is a new technique thatdevelops rapidly and be used widely. The TMS320LF2407 data signal processor of TI Company isused to meet the demands of digital processing. If transmission line occurs fault, starts system, andmeasures the fault point location, then transmits the acquired fault point data to PC by RS-232serial port. The subordinate computer software is programmed by assemble language and the hostcomputer software is programmed by Visual Basic 6.0. The host computer receives data from DSPand stores it in database and the fault point information is analyzed conveniently by the designeduser interface.In order to verifying the feasibility of the fault location method, which is presented in thisthesis, the analog experiment was performed based on the laboratory condition. It shows that the experimental scheme of this thesis is feasible.The single phase grounding fault location system in this thesis can detect the front oftraveling wave, has high accuracy, low cost and good application foreground.