A comparison of overvoltage control methods during three-phase reclosing varying the length of shunt compensated transmission lines

The overvoltage phenomena due to three-phase reclosing of shunt compensated extra high voltage (EHV) transmission lines are analyzed and verified by PSCAD/EMTDC simulation. The study made in an actual 500 kV AC transmission system considers three alternatives in order to limit overvoltages during line reclosing: a developed synchronous switching method, the use of circuit breakers with pre-insertion resistors and the use of metal oxide surge arresters at both line ends. The developed synchronous switching method detects the first minimum region of the voltage beating across the circuit breakers after protection dead time and works independently of zero voltage crossing, reducing significantly the overvoltages and reclosure time. The study was realized taking the line length as an independent parameter.