Steady-state voltage reactive compensation method for half-wavelength transmission lines considering equivalent power supply impedance

Half-wavelength AC transmission (HWACT) refers to transmission along lines with an electrical distance of half the power frequency wavelength. The voltage amplitude at the sending terminal is equal to that at the receiving terminal in steady-state. Furthermore, the voltage at the receiving terminal does not vary with load. However, the electrical distance has been extended in actual HWACT lines because of the impact of the equivalent power supply impedance, so the attractive characteristics no longer hold. As a result, reactive power compensation methods with constant power factor and constant voltage are needed and these are presented in this paper. The steady-state operational characteristics, the calculation methods of additional reactive power compensation and the admittance of a controllable shunt reactor are also given. The methods proposed in this paper are relatively simple to implement, and the calculations involved are straightforward, resulting in effective voltage stabilization. The results indicate that such compensation methods can increase the transmission capacity while maintaining a relatively low voltage along the line.