Numerical Simulation And Characteristics Test Of Temperature Field Under Wire Over-current

Wire is used to connect electrical wiring and transfer electrical energy, which plays animportant role in our daily life. Currently, with the development of the national economyand the improvement of people’s living standards, the demand and use of electrical energyis increasing. Wires caused short circuit, electrical grounding, overload, poor contact andleakage of electricity by long-term run, part of electric line insulation aging and improperoperation, which even led to electrical fires. Recently, the electrical fire in China both thecause of the fire and the direct economic loss of fire were all in the first place of the firestatistics. Electrical fire had been showing the situation of high, and heavy losses majorfires were often caused by electrical fire. Electrical fire had been a major causal factor inour society fire safety, causing huge casualties and property losses. Therefore, the study ofwire’s fault characteristics was particularly important.In this paper, finite element software ANSYS was used to simulate the temperaturefield of conventional copper wires’ short circuited and over-current separately. In theprocess of copper wires’ short circuited, a3D thermoelectric coupling model wasestablished after analyzing the principle of wire’s short circuit. The problem of latent heatwas solved by the enthalpy method. The paper simulated the changes of temperaturefield,got vaporization volume of copper wires and calculated the splash of energy duringtransient short circuit. The research obtained contact area, vaporization volume and shortcircuited current affect the splash of energy.In the process of copper wires’ over-current, the paper simulated the temperature fieldof different size of wires under different laying methods, it calculated the temperature ofthe insulation surface in different current by establishing the thermal fluid coupling modelof copper wires in steady state. The simulation results were compared with experimentaldata to prove the method can be realized. The paper got the highest temperature of theinsulation surface. It also summarized the relationship between critical breakdown current and the highest temperature of the insulation surface of different size of wires underdifferent laying method, providing a scientific basis for electrical fire investigation.