In the situation of load tension or intervention schedule

the transmission capacity of the high voltage transmission line is easy to be increased excessively

which will lead to the risk of overheating. However

the current overheating risk assessment method of the transmission line using aluminum conductor steel-reinforced cannot be directly used for the transmission line using aluminum conductor composite core(ACCC). Hence it is difficult to fully exploit the transmission capacity of the double capacity conductor

and the rate of return on investment is also reduced. The development of ACCC transmission technology is limited. In case of that

this paper proposes a method to assess the overheating risk of the high voltage transmission line using ACCC. Firstly

the thermal circuit model of ACCC is developed based on the thermal balance principle and thermoelectric analogy theory. The parameters of the model are identified based on the off-line experiment and the multi-objective optimization method. Then

the environment thermal resistance sequence is simulated randomly by the online measurement and the Markov chain method. The overtemperature probability of the conductor is obtained under different current levels so that the on-line assessment of the overheating risk of the conductor is realized. Finally

by taking the domestic ACCC as an example

the proposed method is validated by the experimental results.