Phase rotation, also known as phase sequence, refers to the order in which the voltage waveforms of a three-phase electrical system reach their peak values. In a three-phase system, there are three separate voltage waveforms that are 120 degrees out of phase with each other. The order in which these waveforms reach their maximum values determines the phase rotation of the system.
Reactive power is the power that flows back and forth between the electrical system and reactive elements such as inductors and capacitors. It is measured in volt-amperes reactive (VAR). When the reactive power leads the voltage waveform, it is called leading reactive power, and when it lags the voltage waveform, it is called lagging reactive power.