Study on the arc extinction structure of the low voltage DC switch disconnector

Due to the increasing demand for renewable energy systems, such as photovoltaic (PV) systems and energy storage systems (ESS), the need for high-performance breaking capacity in low-voltage DC systems continues to grow. Protective devices such as circuit breakers or disconnectors, often combined with fuses, must cover a wide range of currents and break DC forward and reverse currents during both charging and discharging operations. Particularly, small current where the arcing time is significantly longer than with other current is called critical current and it is challenging to be extinguished because the pressure generated during arc development is too low, resulting in insufficient arc-driving force to effectively move the arc into the arc chute. To drive the arc generated from critical current, electromagnetic force is required. This paper examines the effects of implementing permanent magnets and silicon steel cores in the arc chute and moving contact to enhance the arc-drawing force, using both the finite element method (FEM) and experimental results. The study aims to demonstrate whether the application of permanent magnets and silicon steel cores can effectively improve arc extinction.