Thyristor Based Sequential Switching of Transmission Line Improves Power System Stability

Step change of generator output power (ΔP) at the instant of 3-pole auto reclosing to clear temporary transmission line faults in a power system may be very high. Auto reclosures with high value of ΔP in quick succession may cause damage to the generator shaft. The transient stability limit both with high value of mechanical power input and auto reclosure dead time becomes low. A thyristor based 3-phase static switching device (SSD) in series with the auto reclosing circuit breaker may be employed to reduce ΔP to zero and to improve the transient stability limit to a very high value.