Apparatus and method for controlling flow of power in a transmission line including stable reversal of power flow

摘要

Power flow in a transmission line carrying alternating current is controlled by injecting into the transmission line in series a compensating voltage which is either in phase or 180 DEG out of phase with a reactive component of the transmission line voltage. The compensating voltage is generated by a voltage source converter operated by a controller which determines the angle of the transmission line voltage from voltage measurements taken at spaced apart points on the transmission line. Operation of the inverter in this voltage control mode results in an increase in power flow when the compensating voltage is injected at 180 DEG out of phase with the voltage across the transmission line effective reactance. When the compensating voltage is injected in phase with the voltage across the transmission line effective reactance, the power flow decreases at first from the uncompensated value and can be reduced to zero when the compensating voltage equals the voltage across the transmission line effective reactance without compensation. Further increase in the compensating voltage in the same direction reverses the direction of power flow.