Differentiation research on closing overvoltage of headline-cable comprehensive transmission type with double circuit transmission lines on same tower

摘要

To research the close overvoltage transient characteristic of headline-cable comprehensive transmission type with double circuit transmission lines on same tower, a 220kV power system was selected to build the transient model of headline-cable comprehensive transmission type with double circuit transmission lines on same tower by EMTP, the characteristics of the close overvoltage and the reclose overvoltage after single phase grounding fault were researched totally. Ultimately, the main factors effect on close overvoltage were analyzed. The results demonstrated that the amplitudes of overvoltage were mainly related to close phase angles with its range from 1.17p.u to 2.14p.u. It's best to close at the phase angle from 210°-240° considering the characteristic of arrester. The amplitude of reclose overvoltage was lower than that of close overvoltage. It's appropriate to close the circuit breaker on source side after closing the circuit breaker on the load side to avoid damaging the potential transformer joint with the bus of load. The amplitude of close overvoltage when the transmission line was whole headline was lower than that when the transmission line was headline and cable. It's really possible to occur resonance overvoltage if the transmission line was the whole cable. The amplitude of the over-voltage can be reduced only if the suitable operation types and running types.