The harmonic control project is located in the low-voltage power distribution system of an international hotel in Chengdu High-tech Zone. This harmonic control is aimed at the 2# transformer. The load type is mainly single-phase LED energy-saving lamps, which generate a large amount of leakage current, third harmonic and unbalanced current during the electricity use process. The total distortion rate of harmonic current THD is too large, which causes the grounding protection current of the main circuit breaker at the outlet end of the transformer to be too large, which increases the probability of the circuit breaker tripping, and seriously affects the normal operation and electricity safety of the hotel.

　　In this regard, Chengdu Mailong Electric Co., Ltd. provided a set of active power filters (M-APF380-300-4L/D) on the low-voltage side of the 2# transformer. It was officially commissioned and operated at 02:00 on December 28, 2015. After 72 hours of trouble-free operation, the harmonic control effect was obvious.