With the increasing penetration of new energy in new power system

the influence of the uncertainty of wind power output and the correlation with load on the system operation is increasingly prominent. Thus

the conventional transformer risk assessment can no longer meet the demand. Based on Copula model and Susa model

a joint probability assessment method of transformer operation risk considering wind power and load correlation is proposed. Monte Carlo method is used to calculate each risk index value and evaluate transformer operation risk.The research results show that

the conventional transformer evaluation system that does not consider the wind-load correlation will lead to a low overall risk assessment result

with the maximum error of the index up to 55.02%.Also

with the increase of wind-load correlation

the risk of thermal defects of the transformer is increasing. The research conclusions can assist to improve the accuracy of the operation risk level assessment of new power system transformers

and provide a reference for the later transformer condition assessment and maintenance plan formulation.