An improved secondary voltage control method for half-wavelength transmission system

Abstract

The half-wavelength transmission has the potential application to transmit bulk power through very long distances. In this paper, an improved secondary voltage control method is proposed for half-wavelength transmission system without dependency on remote control signal communication. At first, quantitative relationships between terminal voltages of half-wavelength line and transmission power are deduced based on the distributed parameter model. Then, three main improvements are proposed in secondary voltage control level. Reactive power transmission restriction of half-wavelength line is introduced as another control objective except for pilot bus voltage regulation. Variable pilot bus voltage reference setting method is given according to the voltage/active power correlation considering load fluctuation. Specific voltage control activation conditions are deployed to avoid control direction error or voltage oscillations. After that, simulation results demonstrate that the proposed voltage control method can trace variable voltage reference accurately and flat voltage profiles along half-wavelength line effectively in different disturbance conditions.