1. School of Energy and Power Engineering, Nanjing University of Science and Technology, Nanjing 210094, China;2. Hebei Silicon Valley Chemical Co. Ltd., Handan 057151, China

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.