Voltage sags are a frequent power quality issue in distribution systems. Traditional protection devices, due to their neglect of thermal effects, suffer from low reliability and short lifespans. This paper proposes an optimized design scheme for voltage sag protection devices that considers thermal effects. By establishing a thermal-electrical coupling model, collaborative optimization is achieved in three aspects: the selection of high thermal conductivity materials, optimization of 3-D heat dissipation channels, and intelligent temperature control strategies. Simulation results show that under six typical scenarios, the optimized device?s maximum junction temperature is 18.3-25.7?C lower than that of the traditional device, the thermal equilibrium time is shortened by 40%, and the temperature fluctuation amplitude is only 41.2%-44.1% of that of the conventional device. Furthermore, the optimized device?s response time is shortened to 2.8 ms, the protection action error is controlled within ?2%, and the inrush current is suppressed to less than 1.2 times the rated current. The research demonstrates that the optimized design effectively improves the device?s thermal stability and protection performance, providing technical support for addressing the thermal failure problem of voltage sag protection devices.
Sun et al. (Thu,) studied this question.