In recent years

the problem that voltage is high becomes more and more prominent in case ofthe low load operation of the power grid. It’s urgent need to have deeper generators’ leading phase ability.The generators’ leading phase ability is weaker than their practical ability from analysis of the currentleading phase test

and most units have phase potential. This paper propose three leading phase abilitymining methods

the first method is to improve leading phase ability through changing test conditions

and the next one is the mining method based on the simulation technology

and the last one is the miningmethod based on the measured data. The advantages and disadvantages of these methods are comparedand analyzed

which provides a feasible way to tap the potential of the unit’s leading phase ability and toplay a greater potential in the power grid during the low load period.