Disturbance ride through of SVC stabilizing AC voltage at remote Renewable generations

The Renewable power generations are sometimes located in remote area from the load centers and connected through the long transmission lines. In such case, the AC voltage likely varies along with the renewable power variation. The static Var compensator (SVC) is required to stabilize the AC voltage for stable power transmission [1]. In long transmission lines, the geomagnetic disturbance possibly makes problems [2], which may stop the SVC operation. Without the SVC, the renewable generations are sometimes required to limit its output power. This paper, firstly, discusses the mechanism of the problem which is related to the DC current component induced by the geomagnetic disturbance in the current of the Thyristor Controlled Reactor, TCR, a type of Static Var Compensator, SVC. Without any mitigation, the magnetizing condition of the transformer connected to the TCR may be worsened and may result in stopping SVC operation. Then, secondly, the paper discusses suppression of the DC current component. In the discussion, the paper proposes the practical algorithm for the DC current component estimation for the three phases considering asymmetrical even-order voltage harmonics. Finally, the paper verifies the DC current suppression control through the simulations.