In order to verify the transient action logic and reactive power output characteristics of the new±200 Mvar static synchronous compensator（STATCOM）devices in the500kV Dongguan substation of China southern power grid，the STATCOM is tested by the artificial short circuit in the 220 kV main network. The key to artificial short-circuit is the selection of the short-circuit point. This paper gives out the selection principle of the short-circuit point that can simultaneously meet the transient control mode trigger conditions and the grid security constraints. With respect to the selection principle，the BPA simulation method is adopted to select the short-circuit point. In consideration of the influence of data difference due to the large and small power grid operation modes，suitable data are chosen for simulation data calculation for safety. The base tower N32 of the 220 kV Dongyuan lineⅡis chosen as the final artificial short-circuit test point. It is proved by test results that both the overload capability and transient control features of the STATCOM meet the design standards，showing the rationality of the short-circuit point selecting principle and the simulation method.