The research of the fault law for transmission line has great significant in the state grid maintenance. Firstly

according to the widely monitoring data of wildfire warning and fault data of transmission line in Hunan grid

a study has been conducted on the time clustering characteristic of the wildfire warning risk and fault for transmission line of Hunan power grid

which finds that the number of wildfire warnings risk of transmission line per day follows a power law distribution and the probability distribution of the time interval-frequency including all the triggering factors is verified to satisfy the exponential relationship. Then

the self-similarity of faults time sequences for transmission lines is certificated based on the Allan factor and Fano factor. Further analysis shows that the cumulative probability distribution of time interval-frequency for transmission line faults caused by different natural hazards

such as wildfire

lightning

ice disaster

follows a piecewise power law distribution. The dynamical properties with two time scales of transmission line faults are analyzed. Finally

the research results obtained can provide the theoretical reference for the prediction of wildfire warning risk and faults of transmission line.