The influence of large-scale photovoltaic plant on transient stability of power system is researched from the perspective of domain

and the conventional generator is replaced by the photovoltaic plant with equal capacity to calculate the LPV-DSR（Dynamic Security Region with Large-scale PhotoVoltaic plant）. Extensive simulations of typical power system show that the boundary of LPV-DSR can still be fitted by hyperplane. Three conclusions are obtained by the comparison with DSR of the system before the connection of photovoltaic plant: the boundary of LPVDSR is approximately parallel to the DSR boundary of the system before the photovoltaic plant connected; from the perspective of system transient stability

the optimal control strategy of photovoltaic converter is constant active power control and constant AC voltage control; the DSR range changes monotonously with the increase of grid-connected photovoltaic capacity under the same control strategy.