Overvoltages on a transmission line with both ends open
I experienced a bizzare phenomenon on one of my 400kV transmission line. it is a 238km Long 400kV line with 125 MVAr non-switchable line reactor at one end and 50 MVar switchable reactor at another end. The Reactor was connected through a breaker at the other end. At our end the reactor isolator was open. The moment we closed the isolator which connects reactor to transmission line, heavy overvoltages built up in the system even though the line was isolated from both the ends. The voltage magnitude went upto 600kV level persisting for a long time until the switchable reactor was taken out of service by opening reactor breaker at the other end. Please explain why this voltage came on a dead line???
I experienced a bizzare phenomenon on one of my 400kV transmission line. it is a 238km Long 400kV line with 125 MVAr non-switchable line reactor at one end and 50 MVar switchable reactor at another end. The Reactor was connected through a breaker at the other end. At our end the reactor isolator was open. The moment we closed the isolator which connects reactor to transmission line, heavy overvoltages built up in the system even though the line was isolated from both the ends. The voltage magnitude went upto 600kV level persisting for a long time until the switchable reactor was taken out of service by opening reactor breaker at the other end. Please explain why this voltage came on a dead line???
If these are series reactors, then consider testing with a shunt reactor or dummy load. I may be a high impedance resonant coupling from adjacent power lines. The Q resonance factor is a function of the rise time and frequency.
ReplyDeleteYvonne, did you learn the reason for this ? was it line capacitance resonating with reactor with no. load impedance?
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