EFFECTIVENESS OF PRE-INSERTION INDUCTORS FOR MITIGATING REMOTE OVERVOLTAGES DUE TO SHUNT CAPACITOR ENERGIZATION

Energization of shunt capacitor banks on power systems can potentially create significant overvoltages both at the location of the switched bank and at other locations in the system. Pre-insertion resistors hav e been used for years by the electric utility industry as one method o f controlling these capacitor bank energization overvoltages. Recently , pre-insertion inductors have been introduced as a cost-effective alt ernative to pre-insertion resistors. The results of a system study inv estigating remote overvoltage mitigation methods for shunt capacitor s witching have shown that pre-insertion inductors are not always as eff ective as pre-insertion resistors. A parametric study has been perform ed to determine the effectiveness of pre-insertion inductors for contr olling remote overvoltages, such as those at the end of open-ended lin es or transformer-terminated lines. The results of the parametric stud y show that the pre-insertion inductors used for controlling remote ov ervoltages may become completely ineffective for certain system condit ions. This finding is explained in terms of the physical phenomena.