Reactive power represents the portion of electrical power that oscillates between the source and the load, without performing actual work. It arises from inductive and capacitive components within electrical circuits. A common unit used to quantify it is the Volt-Ampere Reactive (VAR). Its presence indicates energy is being stored and released in components like inductors and capacitors, contributing to current flow without contributing to net energy transfer. For example, in an AC motor, reactive power is necessary to establish and maintain the magnetic field required for operation, but it does not directly contribute to the shaft power output.
Effective management of this oscillating power component is crucial for maintaining system stability and efficiency. Excess generation or absorption can lead to voltage fluctuations, reduced power factor, and increased transmission losses. Historically, uncontrolled fluctuations in this component have contributed to system instability and even blackouts. Optimizing it improves grid performance, reduces operational costs, and maximizes the utilization of existing infrastructure.