Abstract
This paper describes a self-commutated type Static Var Compensator for suppressing voltage fluctuations caused by an ac electric railway. (Shinkansen, or New trunk line). The ac electric railway is a singlephase load with large changes of reactive power, and causes large voltage fluctuations and power unbalances among three phases. The authors have developed a new voltage fluctuation compensating system using a self-commutated Static Var Compensator. This system has functions of both reactive power compensation and negative-sequence current absorption and can suppress the rapidly changing voltage fluctuations caused by an ac electric railway, effectively. The system of 40MVA has been put into practical use, first in the world, in 1993. The test results at site showed that it has excellent performance characteristics.
In this paper, the theoretical analysis on the characteristics of voltage fluctuations with or without the compensating system and the evaluation of the test results are described.
