Lightning strike causes a large lightning voltage injection into grid-connected PV systems at the point between inverter and transformer. The overvoltage resulting from the lightning-impulse voltage is a major concern for the multiple expensive electrical devices of the grid-connected PV system and to be studied in depth in order to decrease the damage caused by this overvoltage. In this paper, PSCAD/EMTDC software simulated the complete model of the system. In this work, the point which selected from grid-connected PV system to inject impulse lightning voltage is between transformer and inverter. In different locations of the grid-connected PV system, lightning overvoltage has been noted by injecting impulse lightning voltages. In this paper, the surge arrester is used to mitigate the lightning overvoltage on the PV array. STATCOM is used to improve voltage of the PV array. The results show that in case of using the surge arresters and STATCOM, the lightning overvoltage is mitigated.