Negative sequence current reduction for generator/turbine protection

The authors present a feasible method for negative sequence current reduction at the generator terminal through a special function static VAr compensator (SVC). A specially designed fixed-capacitor thyristor-controlled reactor SVC is used. Computer simulation and laboratory test results show that it can effectively reduce negative sequence current at a generator terminal. Since this compensation circuit is operated in an unbalanced mode, both characteristic and noncharacteristic harmonics will appear in the system; careful design of the harmonic filtering circuits is thus necessary