CAPACITOR BANK SWITCHING
Power Utilities use capacitor banks in distribution lines for power factor correction and to maintain acceptable voltage levels. The capacitor banks improve the power factor, thus decreasing the amount of reactive power consumed. This benefits the utility company by allowing them to provide additional power capacity during peak demands and in fast growing areas.
However, utility capacitor bank switching can have negative impacts on power quality. Utility capacitor bank switching transients can be magnified at low voltage capacitor locations on customer power systems, causing premature failure of sensitive electronic equipment. The capacitor bank energizing transient is important because it is one of the most frequent utility system switching operations.
Power quality symptoms related to utility capacitor bank switching include: customer electrical and electronic equipment damage or failure (due to excessive overvoltage); nuisance tripping of adjustable-speed drives, production or process equipment shutdown and computer problems.
Protection from the harmful effects of capacitor bank switching can be achieved through the use of surge protection devices (SPDâ€™s). Properly sized and correctly installed surge protection devices can prevent harmful voltage transients from damaging electrical equipment.