1.Project Overview
The equipment installation site is a large commercial store, which is divided into various exhibition and sales areas such as shopping mall billboards, lighting, supermarkets, exhibition counters, etc. A large number of single-phase loads and LED lighting and LED advertising display light equipment are used. These equipment generate a large number of The third harmonic of the system is superimposed in the N-phase cable of the system, causing a huge current in the N-phase cable of the system and causing cable heating.
2.Distribution system diagram
3.Governance effect analysis
Current data
Before the active harmonic filter is turned on, the load current waveform at the lower end of the incoming line switch obviously deviates from the sinusoidal waveform. The effective value of the A/B/C three-phase current is about 170A, and the N-phase current is about 270A.
Before the active harmonic filter is turned on, the load current waveform at the lower end of the incoming line switch is processed and restored to a sinusoidal waveform. The effective value of the A/B/C three-phase current drops to about 150A, and the N-phase current drops to about 30A.
Before the active harmonic filter equipment is turned on, the total harmonic current distortion rate of the load current at the lower end of the dual power switch is about 65%, and the main harmonic distortion orders are 3/5/7 harmonic current distortion.
After the active harmonic filter is turned on, the total harmonic current distortion rate of the load current at the lower end of the switch drops to about 5%, and the 3/5/7 major harmonic distortion times all drop significantly.
After installing our active harmonic filter (AHF), the harmonic current distortion rate of the load at the lower end of the 0.4KV low-voltage side switch in shopping center has been significantly improved. The current flowing through the N phase has increased from about 270A to the initial level. , down to 30A, which greatly ensures the safety and stability of the system and reduces the occurrence of N-phase cable heating, insulation aging and fire hazards.
