Research On HVDC Transmission Line Fault Location Method

HVDC system in China is developing rapidly，and it plays an important role in theproject of power transmission from west to east and national networking. However, theHVDC transmission lines are usually long, the crossing terrains are complex, the climateconditions are changeable, as a result, it is not easy to patrol and inspection when the linefault has happened. Therefore, the study of the HVDC transmission lines fault location hasimportant significance in achieving reliable, accurate fault location, repairing the fault linetimely, reducing outage losses, so as to ensure the reliability of power supply and to improvethe security and stability of power system economic operation. When HVDC transmissionline fault has happened, there will be traveling wave spreading along the line. The travelingwave signal is a kind of non-stationary signal with mutation, and the" mutation" containsthe fault time, fault location and other important information, an accurate and effective faultlocation method can be built if the fault information had been picked up and analyzed.Independent component analysis method is a kind of signal processing method based onhigh order statistical properties of signals that is developing in recent years, while the prioriknowledge are unknown, this kind of method can separate the independent signals fromhybrid signals on multi-channel successfully. The voltage or current values of HVDCtransmission lines are actually made up of many waves’ values, and these waves areessentially independent. In this article, the independent component analysis method is appliedto HVDC transmission line fault location, and the fault location method based on FastICAalgorithm is proposed. By using FastICA algorithm to analyze the transmission line voltageand current signals containing the traveling wave, the traveling wave feature signals can beextracted, according to the transmission line single terminal traveling wave fault locationtheory, it is necessary to calculate the time of the initial traveling wave head and the secondtraveling wave head from the fault line arrive to the measurement point, and to estimate thepolarity relationship between these two wave heads, so as to make fault location.In addition, the Matlab software is applied to make simulation in this article, the HVDC system model is established, and the FastICA algorithm is used to make simulation analysis offault location when line fault has happened on different positions and with differentresistances on the transmission line, the simulation results have shown that the proposedtraveling wave fault location method based on FastICA algorithm is accurate and effective.