Examination of the definitions of voltage unbalance

In this paper, various definitions of voltage unbalance are explored and compared, and their proper application conditions are examined as well. A popular optimal algorithm, the genetic algorithm, is adopted to investigate the differences among various definitions of voltage unbalance. By fixing the numerical value of the concerned definition of voltage unbalance, the maximum and minimum values of the true definition of voltage unbalance are found and compared. Finally, suitable conditions to apply the definitions are drawn.

► LVUR% and two AFs are useful under low voltage unbalance.
► PVUR(2)% are commonly larger than other definitions mentioned in this paper.
► AF(2)% is generally more precise than AF(1)%.