Analogical Transfer between Heat Transfer and Electrology: (2) Engineering Practices

To verify the feasibility and engineering practice value of the transfer analogy theory between heat transfer and electrology, this paper presents two typical applications addressing practical problems in the field of electrical engineering. Firstly, in view of lack of calculating method for the current carrying capacity of cable lying through unfavorable heat dissipation regions, we establish the radial thermal circuit of cable with the aid of thermal-electrical analogy analysis. The thermal resistance of insulating material and the loss in each layer of cable structure are equivalently evaluated, and further, the thermal circuit model with distributed parameters is constructed. The thought of solving the cable temperature distribution and carrying capacity is given, which compensates the insufficiency of the current calculation method recommended by IEC standard. Secondly, for the limitations of the prediction methods of hot-spot temperature in transformer, we develop the thermal circuit model with centralized parameters by incorporating the heat transfer process of transformer and the thermal-electrical analogy. Applying Kirchhoff current law to the thermal circuit model, a faster prediction method for calculating the hot-spot temperature is proposed. It is verified that the model has higher prediction accuracy than the method recommended by IEC standard. The results indicate that the thermal-electric analogy can solve engineering problems more practically and the transfer analogy can promote innovation and development of many interdisciplinary researches. © 2021, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.