Harmonics and Dynamic Response of a Virtual Air Gap Variable Reactor

As more sustainable energy generation is integrated into power grid, the control of power flow in an efficient and effective manner becomes more and more essential. A new innovative device is presented that allows the control of line power flow without the high harmonics and efficiency losses of traditional methods. This paper presents the dynamic response and the harmonics of a laboratory prototype Virtual Air Gap Variable Reactor (VAG-VR) and compares them with those of a thyristor controlled reactor (TCR). Variable Reactors have many applications in the power industry. Their use allows control of line power flow, voltage regulation, as well as damping of power oscillations and sub synchronous resonances. A variable reactor is most commonly implemented as a TCR by switching in and out a constant reactance to achieve an averaged variable reactance. By using a virtual air gap, implementation of a continuously variable reactance is possible with a better dynamic response and without introducing the harmonics created by the thyristor switching of a TCR.