Accurate assessment of lightning protection capability of transmission lines is of great significance on the power network security and economic operation. Insulator lightning flashover criterion is the key to the realization of accurate lightning level analysis. Therefore

we experimentally investigated and simulated the flashover characteristics of the true type cup-tower under short tail wave impulse and in the high-altitude area. A short tail wave impact test was carried out in high altitude area for insulators of 220 kV cup-tower. Analyses of the test results show that the flashover characteristics of insulators with different suspension positions on the cup-tower are within 3%

the flashover characteristics of the insulators hanging on the cup-tower are different from those of the rod gap and the insulator out of the tower. The simulation results show that the volt-second characteristic curve proposed by IEEE and the existing leader development model coefficients can not accurately describe the flashover characteristics of insulators in cup-tower under the impulse of short tail wave in high altitude area. Based on experimental data and long gap leader development theory

a leader development model of composite insulator on cup-tower in high altitude area is proposed. The difference between strike-back lightning-withstand level of transmission lines when different flashover criteria are adopted for insulators is analyzed by simulation. The results provide a reference for analysis of strike-back lightning-withstand of 220 kV transmission line in high altitude area.