Control Systems for On-Load Tap-Changers

The quality of electrical energy is of great importance for modern electrical networks. The stability of the nominal voltage is one of the main parameters of this quality. To ensure this stability, on-load tap-changers integrated into the power transformers are widely used. Classical tap changing schemes have some drawbacks, and because of this more and more semiconductor assisted schemes and schemes with vacuum interrupters are used. The paper presents various control systems designed for diverter switches of on-load tap-changers with special elements. Their advantages and disadvantages are discussed. Specific implementations of different types of control systems are considered.