One-terminal fault location for HVDC flexible transmission lines based on wave voltage distribution features

A one-terminal fault location method for high voltage direct current (HVDC) Flexible transmission lines based on distributed parameter model is proposed. As high-capacity capacitors are connected to both ends of HVDC Flexible transmission lines, in the network of one-mode fault component, the voltage travelling waves have the following two features: total reflection of voltage traveling wave occurring at both DC buses of two-terminal HVDC transmission system and at the fault point the refraction of traveling wave stronger than the reflection; the polarity of voltage traveling wave changed due to reflection rather than refraction. Then, the voltage distribution of the first reflected wave at the measuring point and its forward path can be calculated. Finally, the strongest positive switching point in the voltage distribution can be found, and the distance from this point to the opposite terminal is the fault distance. This method has a satisfactory precision and is not affected by transition resistance theoretically. Besides, there is no need to artificially recognize the wave front of the traveling wave and the automation of fault location is easy to implement by use of the proposed algorithm. Simulation results show this method is applicable to the whole line.