Observation of Residual Voltage in Low-Voltage Surge Protective Devices Due to Nearby M-Components

This paper presents experimental results obtained from the Guangdong comprehensive observation experiment on lightning discharge during summer 2014. Residual voltages and current flows in a surge protective device (SPD) connected to an overhead distribution line were observed due to nearby M-components of a triggered lightning flash. Residual voltages with varying characteristics caused by different M-components are analyzed at two terminals of the SPD, and corresponding formation mechanisms for the different characteristics are also discussed. Our results show that the residual voltages at two terminals of the SPD caused by three types of M-component are determined from both the line induction and the ground potential rise (GPR) in a nearby triggered lightning at 40 m distance. The M-component with a large peak current would produce large surge energies in the power line. Under a given peak current, the M-component has greater surge energy than the return stroke. The ground terminal of the SPD is still affected by the GPR, and our results also show that the continuing current superimposed with M-components is an important factor in determining the magnitude of line coupling in power distribution lines when a lightning flash occurs nearby.