ABSTRACT
One of the key responsibilities of a distribution utility is voltage regulation. Voltage regulation refers to maintaining acceptable voltages at all points along the distribution feeder including secondary service circuit under all loading conditions. Most of the utilities in the U.S. follow ANSI C84.1 voltage standards (NEMA 2016) for maintaining acceptable levels of service voltages. The service voltage is the point where the electrical systems of the supplier and the user are interconnected which is normally at the meter. According to ANSI C84.1, the service voltages should be within ±5% of their nominal voltage level which translates to 0.95 to 1.05 per unit (pu) voltage. When a service voltage goes below 0.95 pu, it is considered as an undervoltage violation and if the service voltage exceeds 1.05 pu, then it is an overvoltage violation. For voltage regulation, traditionally, utilities employ the load tap changer (LTC), line voltage regulators, and
fixed or switched capacitors. These electromechanical control devices are installed on the primary feeder and are controlled either in centralized or decentralized fashion to perform the voltage regulation.
