With the continuous growth of grid connected photovoltaic capacity

the influences of PV on the transient stability and corresponding countermeasures have become an important research topic.Consequently

we analyzed the active and reactive power characteristics of PV unit and its grid connected system during rapid voltage dropping and lifting

and analyzed the influences of different control modes on these characteristics firstly.Thereby

aiming to the sending system with conventional generator and photovoltaic

we analyzed the influences of PV on transient stability

and proposed countermeasures.Simulation results got from Hetian area of Xinxiang Uygur autonomous region have verified that the proposed countermeasures can improve the transient stability of sending system with conventional generator and photovoltaic effectively

and these countermeasures provide technical solution to enhance the acceptance capacity of photovoltaic power.