The effective component in an AC power grid refers only to the power frequency. Any other component is called a harmonic. The harmonic is generated due to a sinusoidal voltage being applied to the non-linear load, which distorts the fundamental current. With a continuous development in science and technology, the non-linear electrical equipment has become increasingly popular for use in the power systems.
2. Reactive Power
Reactive power refers to the power that oscillates or travels between the load and the power supply, and does not convert to other forms of energy (such as mechanical, optical, thermal, chemical or others). In the power distribution system, the running equipment consumes both the active and reactive power. Reactive power is sometimes referred to as VAR.
3. Three Phase Unbalance
Three phase unbalance means that the three phase current (or voltage) amplitudes are inconsistent, and the difference exceeds the specified range. In a power grid, the main reasons behind a three phase unbalance include an uneven distribution of single phase loads, uncontrollable load connection times to the grid, asymmetric three phase loads and a resonance in the power grid.