Power frequency over-voltage of 500 kV four-circuit lines on the same power

The 500 kV four-circuit lines on the same power to be built in China is the first one in the world.The power frequency over-voltage,the secondary arc current,and the recovery voltage of the lines with different tower types and various phase order arrangement are studied under different system operational modes.The influences of tower types and phase orders on the power frequency over-voltage and the secondary arc current are analyzed,and conclusions and suggestions are proposed.