Relay protection for half wavelength AC transmission line

Either under normal condition or fault condition, the characteristics of the voltage and current of half wavelength transmission line are different from the characteristics of the ordinary short line, for its transmission distance is much longer the voltage level is much higher than the ordinary transmission line. Its distributed-parameter characteristics are notable, and distributed capacitance is large. The over-voltage caused by capacitance effect is a big problem. The traditional transmission protection strategies can not be directly used in this kind of line. But at the same time, study on half wavelength transmission protection is scarce. Analysis and calculation of the transmission line under fault condition were conducted in this paper based the Bergeron model. And the effect of the distributed capacitance is taken into account, and the capacitance current is automatically counted in. A kind of novel protection strategy suitable for half wavelength transmission line is proposed, which is based on the Bergeron model. A mass of simulation experiments base on the simulation software PSCAD have been done and the results showed that the novel line protection strategy is suitable for half wavelength transmission line.