On overvoltage suppression method on 66kv straight hanging SVC based on PSCAD

In recent years, the situation of SF
₆
circuit breaker which is used to switch 66 kv voltage class SVC is gradually increasing. According to the practical operation experience, however, it is often seen that overvoltage accidents of phased reactor burned when SVC is cut by SF
₆
circuit breaker, which endangers the safety of electric power equipment and influences the normal operation of power system. It shows that the research of overvoltage of phased reactor which produced when SVC is cutted off is significant. Simulation model of a 220 kV substation 66 kV straight hanging SVC device is established by PSCAD software, transient process of all sorts of possible overvoltage is simulated in the process of cutting SVC, instantaneous voltage is simulated and analysed when the lightning arrester is installed respectively in between TCR line and ground, TCR branch in parallel and the three-phase, instantaneous overvoltage of all kinds of devices including RC absorption device and the other combination devices is simulated and analysed. Lightning arrester installed in different locations will have different inhibiting effect on overvoltage, the overvoltage suppression effect is also different with RC absorption device having different parameters. It is concluded that the overvoltage is well restrained by the lightning arrester connected to reactor in parallel, and reasonable parameters of resistance capacity of absorption device also can restrain the overvoltage, Finally according to the actual situation of a substation, lightning arrester connected to reactor in parallel to suppress overvoltage is selected.