Simulation and testing of novel Ferro-Transient Suppression Circuit for CVT

In this paper a typical 400 kV CVT is simulated for Ferroresonance and Transient Response conditions using Active and Passive Ferroresonance Suppression Circuits (FSCs) available in the literature. The effect of the FSC and other parameters on the transient response is analyzed. A novel thyristor based Electronic FSC is proposed in this paper which is suitable to suppress both the Ferroresonance and the transient response oscillations in a CVT. The hardware of the Electronic FSC is designed and validated for both the Ferroresonance and the transient response conditions using the simulations as well as the laboratory tests. The simulations and laboratory test results show that, with the new Electronic FSC, the Ferroresonance is suppressed within 5 cycles and the CVT is meeting all transient response classes (3PT1, 3PT2, and 3PT3) of IEC 60044-5. The simulation of the CVT is performed using PSCAD/EMTDC. Some practical concerns of this solution are also addressed.