Shunt capacitor bank switching solutions for transient mitigation - design approach and EMTP simulations

Shunt capacitors provide a cost-effective solution to alleviate voltage constraints in HV/EHV power systems and are widely used for voltage and reactive support. However, during planning and design phase, engineers are often faced with a challenge to choose appropriate transient mitigation/control arrangements ranging from pre-insertion resistors/inductors and current limiting reactors (CLRs) to synchronous closing breakers. Further, there may be a need for application of other mitigation measures such as surge arresters and surge capacitors. While the first variable in the design process is selection of appropriate switchgear, other variables include, choosing an appropriate location for CLRs, surge arresters, surge capacitors, and their sizing. This paper describes the evaluation of transient concerns for single and multiple shunt capacitor bank switching, followed by a step-by-step procedure for application of transient mitigation measures. Case study for a 230 kV shunt capacitor bank addition is presented along with simulations using Electromagnetic Transients Program (EMTP).