Synthesis Method Research On Fault Locating In High-tension Transmission Line

Quick and accurate localization of faults is the basic task of fault location as well as an important research subject in power system relay protection. Transmission lines are responsible for the delivery of electric energy and their faults influence the safe operation of power system directly. Fault points must be found out soon according to various fault features through fault location, and then burden of linesman is lightened; faults can be cleared in time to recover power supply of transmission lines quickly, so that the economic losses resulted from power failure is reduced, which can also help to find out incipient fault of insulation to ensure the safe and stable operation of electric net work.Having suggested that one kind of new single fault locating method based on the traveling wave of wavelet modulus maxima combining with impedance method. Firstly, traveling wave calculate single fault location, the fault distance is calculated based on the interval between the incident traveling wave and the reflected traveling wave from the fault point in one terminal fault locating. As far as it goes, it is difficult to distinguish between the reflected traveling waves from the fault point and from the remote bus. The innovate of this paper is consist in no distinguishing the reflected traveling waves from the fault point and from the remote bus, as well as in site of bus's refracted traveling waves, so find many fault locating result, then the single terminal algorithm which measure resistance filtrate the fault locating result based on traveling wave, choice one nearly result as the fault locating result. A lot of simulation results by Matlab show that the algorithm is not affected by the faulty position and the fault modes, is diminutively affected by transition resistance and the other terminal's changes of power system operating modes. The algorithm is quite robust, high practicality.A new approach to fault location based on distributed parameter model, whose voltages and currents of the two ends of the transmission line do not need to be measured synchronously, is presented in this paper. To locate the fault, in this algorithm the current and voltage phases at the two ends of transmission line and the distributed parameter model are adopted in the on-line calculation of positive sequence parameters of equivalent circuit model of transmission line, and the non-determinacy problem of the line parameters during the operation is solved. To implement the two terminals fault location the mutation quantities before and after the fault are acquired from the data sampled at both ends of the transmission line, the equivalent system impedances for single circuit transmission line on same tower, which are applied to the fault location, are calculated by the symmetrical components respectively. The algorithm uses one dimension search method to look for the faulty position according to regularities of voltage distribution along the transmission line after the fault. Then the line parameters can be on-line computed by both the voltages and the currents of the two ends of transmission line before the fault. The DFT based filter combined with a band2pass filter help to extract extremely accurate fundamental frequency components for calculation of fault location. A lot of simulation results by Matlab and the testing data from practical power systems show that the presented algorithm possesses high fault location accuracy, this algorithm can adapt the changes of power system operating modes and is not affected by the transition resistance ,the faulty position, the fault modes, and incidence angle of the fault occurrence to the faulty point.