抄録
A 50 MVA Self-Commutated Static Var Compensator (SVC) using world largest GTO thyristors rated 6kV-2, 500A has been developed for voltage control of electric power system. The rated DC voltage is 16.8kV which is four times higher than the highest one manufactured so far. To achieve the high DC voltage, 8 GTO thyristors are connected in series. Voltage unbalance between GTOs during switching transient was investigated. A new overcurrent limiting method is proposed, since conventional fuse protection can not be applied due to such high voltage. Newly developed technologies for this large and high voltage self-commutated SVC are described.
Although simple star-delta connection transformers are used, harmonics generated from SVC are almost equivalent to 24 pulse converter by shifting the pulse timing appropriately. The PWM control based on 150Hz is applied and the SVC is designed to continue operation during system faults. The performance of controller is successfully tested by a simulator, and typical test results are introduced.
