Operating Mechanism Of Low-voltage Pole-mounted Circuit Breakers In Large-scale Power Grids

Lv Pole Mounted Circuit Breakers combines an arc-extinguishing mechanism with a thermomagnetic tripping mechanism. The arc-extinguishing structure can quickly eliminate the electric arc upon disconnection, preventing damage to equipment caused by sparks and high temperatures. The thermal trip unit is sensitive to continuous overload, while the electromagnetic trip unit is sensitive to transient short circuits. Together, they enable the differentiation and handling of different fault types.

At the low-voltage output end of the pole-mounted distribution transformer, the low-voltage pole-mounted circuit breaker plays the role of feeder protection. It monitors the bus current, and when the branch load is too high or an imbalance occurs, it trips to disconnect the power, thereby isolating the faulty section and maintaining the stable operation of the remaining lines.