Lightning Risk Assessment of 330 kV Transmission Line Under Icing Conditions in Qinghai Area

Icing and lightning strikes are the main causes of transmission line faults. Currently, the lightning strike risk assessment methods are too singular. The impact of icing on the electrical performance of the line is not comprehensively considered, resulting in assessment results that cannot reflect the actual lightning strike risk of iced-up lines. Therefore, a lightning risk assessment method considering icing factors is proposed. The method establishes an icing thickness calculation model based on the weighing method and uses the electromagnetic transient analysis software (Electro Magnetic Transient Program, EMTP) to write a preliminary flashover criterion module for icing insulators. In order to more accurately calculate actual line shielding, an improved electrical geometry model considering lightning incident angle and ground slope is established. Finally, the lightning strike tripping rate is calculated using the above model, and the towers are assessed for risk level based on risk classification standards. This evaluation method can provide a new reference scheme for the design of risk assessment systems for transmission lines in China.