A proper lightning overvoltage protection for photovoltaic (PV) arrays is crucial to their long-term stable operation. The damage caused by lightning induced overvoltage to a PV array is analyzed. The equivalent circuit of the PV array is modelled in the EMTP with the consideration of transient models of PV cells as well as the lightning overvoltage coupling characteristics of PV modules. The values of surge overvoltage across the inverter port and bypass diode and the potential differences between a DC cable and a metallic frame are calculated when lightning stroke the isolated rod, and the protective effects of surge protection device (SPD) and transient voltage suppressor (TVS) under varying waveforms of lightning current are discussed. Results show that if SPDs are only installed at the port of an inverter, induced overvoltage across the inverter port can be suppressed to some extent while the large-amplitude overvoltage may occur across the bypass diode and potential differences may occur between the DC cable and the metallic frame. When SPDs are installed on both sides of the PV string, the overvoltage of all the equipment is significantly suppressed. The amplitude of lightning induced overvoltage is obviously affected by the wave front time of lightning current, and a short wave front time may result in an increase in the amplitude of induced overvoltage. However, a risk of permanent breakdown still exists for the bypass diode in the case of a very short wave front time. It is suggested that SPDs should be installed on both sides of the PV string while adding an extra TVS in parallel with the bypass diode, so as to realize reliable protection for PV array against lightning induced overvoltage.