The low-voltage reactive power compensation cabinet is mainly used in low-voltage distribution rooms, in parallel with distribution cabinets, for centralised compensation of system reactive power, improving power factor, reducing system reactive power loss and improving power quality. The device can automatically change the compensation capacity according to the change of system reactive power, so as to achieve excellent compensation effect. It can be widely used in metallurgy, mining, building materials, machinery manufacturing, light industry, chemical industry, port and other industries, and is especially suitable for industrial and mining industries with large load changes.