
431Electromagnetic Disturbances in PowerSystems and Customer Homes
of the proposed method is lower than that of the common method. In the
common method, a larger current ows to the resistor, because the PD expe-
riences a discharging lag. However, in the proposed method, the current
owing to the resistor rapidly decreases because the varistor works quickly.
Therefore, the proposed method can reduce the maximum voltage more ef-
ciently than the common method can.
Figure 6.25b indicates that the maximum and steady-state values of the
proposed method are lower than those for individual grounding. Because
the varistor has a capacitance of hundred ...