Calculation and protection on the lighting intruding waves of 550 kv GIS substation.

Electromagnetic Transient Programme has been used to calculate the lightning intruding wave of 550 kV GIS substation. The effects of mode operation, surge impedance and length of cable have been considered in the process of calculation. Besides, the corresponding protection scheme has been proposed on the basis of the results of calculation. Results of the research show that when the system is operating in single-in-single-out way, the voltage intruded into the substation is highest; the bigger of surge impedance for GIS, the higher of the voltage; the overvoltage amplitude decreases with the increase of the length of the cable; the installation of metal oxide arrester (MOA) at the entrance of GIS and the region close to the transformer or using the reactor instead the arrestor at the entrance of GIS can limit the voltage strike on the transformer effectively. [ABSTRACT FROM AUTHOR]