Simulating calculations of transient voltage on insulating sheath along a long-distance 500kv XLPE submarine cable

Summary

The first transmission line with a long-distance 500 kV AC cross linked polyethylene (XLPE) submarine cable combined with the overhead lines will be built in Zhoushan 500 kV AC transmission project. The high transient voltages caused by various switching operations or lightning strikes on the insulating sheath (or oversheath) of submarine cable, except of on the cable insulation, will challenge the safe operation of transmission lines. In order to clarify the characteristics of various transient voltages on the insulating sheath along a long-distance 500kV AC XLPE submarine cable, the models of simulating calculations were established with PSCAD/ EMTDC software based on the Zhoushan 500 kV AC transmission project. The transient voltages on the insulating sheath of submarine cable, including the induced voltages caused by the line faults, switching operations and lightning strikes were calculated. And the characteristics and distributions of various transient voltages on insulating sheath along a long-distance submarine cable were obtained. The simulating calculations results indicated that the induced transient voltages on the sheath of submarine cable caused by a single-phase metal grounding fault could be 7.50 kV And the operation of switching off a no-load line, when considered the re-striking of circuit breaker, would cause the induced transient voltages a peak of 3.30 kV. The highest induced transient voltages caused by lightning strikes could be 11.8 kV when the lightning current reached the maximum value. In the normal cases, the highest induced transient voltages on the sheath tended to locate at the middle of the long-distance cable.

Additional informations

Authors

LØVÅS, HARTMANN, GERMANN, KUNTIA, KURRAT

Keywords

transient voltages, Zhoushan project, submarine cable, sheath, grounding body