Power Enhancement by Transmitting AC-DC Power Simultaneously-An Experimental Implementation

Abstract

Power transfer enhancement has become an issue because of thermal and stability limitations associated with AC transmission. This paper presents a model at which transmission lines are loaded near to their maximum ampacity unlike the existing AC power systems. The proposed concept is known as simultaneous AC–DC transmission where the existing AC lines can carry AC current with DC superimposed on it without major structural modifications. Power transfer capability of 70-km transmission line is enhanced by converting a fraction of AC power from the existing system to DC power which will be put in the sending end transformer through the neutral. Transformer zigzag connection eradicates the issue of core saturation that results from superimposed DC component. Transmission line data is provided by Qatar general electricity and water corporation (Kahramaa). Theoretical and real-time simulation results show that power transfer capability has been enhanced by 89%. Transmission angle is increased beyond 30°. MATLAB\Simulink and real-time digital simulator (RTDS) are two different softwares used to model and simulate the AC–DC transmission system offline and in real time, respectively. Laboratory prototype shows that power transfer capability has been enhanced by 33%. Practical results and waveforms had been recorded using the power analyzer PA400.