Study on the Temperature Rise Suppression Characteristics of Large-Capacity Generator Outlet Vacuum Circuit Breakers with Forced Air Cooling

Large-capacity vacuum generator circuit breakers play a key role in power plants and are essential for the protection of generators and the safe operation of power systems. As generators are usually operated at full load for a long time, high currents can cause serious heat generation and temperature rise at the circuit breaker, which may lead to insulation deterioration, mechanical strength loss, accelerated aging and reduced opening performance, seriously threatening the safe operation of the generator. In addition, SF6 circuit breakers are commonly used in large power stations at present, and SF6 is an extremely powerful greenhouse gas, which can lead to serious greenhouse effect and contradict the dual-carbon goal of national development. In order to improve the rated current and environmental performance, it is imperative to research and develop new large-capacity vacuum generator circuit breakers. In this paper, for the vacuum circuit breaker, according to the nuclear power plant generator circuit breaker mainly rely on the actual application of forced air cooling heat dissipation, the establishment of the forced air cooling model, the study of high air temperature and high air speed and low air temperature and low air speed two conditions of the heat dissipation, and get the temperature and the flow field distribution, in the two kinds of wind temperature and wind speed conditions, can be the core interrupter chamber parts of the temperature rise control in about 66 °C. Subsequently, the forced air cooling temperature rise experiment was carried out, and the experimental results were compared with the simulation results, and it was found that the error was basically within 5K, which proved the reasonableness of the forced air cooling model, and it was obtained that the main reason for restricting the heat dissipation was that part of the air inside the cylinder was not involved in the flow. Finally, simulation calculations and comparisons are carried out by changing the parameters of the forced air cooling to enhance the heat dissipation program, in order to make the temperature rise of the circuit breaker at the rated current of 33kA meet the requirements.