APF Shopping Mall Application

1. Project overview

Martial arts trust-mart shopping mall is a large commercial store, internal counter for supermarkets, sales, and other sales areas, use a lot of single-phase load and LED lighting, LED advertising display light equipment, these devices produce a large amount of 3rd / 9th order harmonics, these harmonic stacks in N phase which leads much current and heat problem on N phase, the heat of dual power switch getting higher, the dual power switch tripped due to over-temperature protection.

2. Test record

2.1. Arrived at the project site at 18:00 on August 14, 2020, moved APF into the on-site power distribution room, prepare the relevant installation and debugging preparations. The on-site customer indicated that Blackouts could be allowed after the store closed at 21:30 at night.

2.2. Wiring preparation

2.3. Test the actual power quality situation on the site again to check the power quality data and waveform before the APF was installed on the site.

2.4. At 22:00 PM, on-site power blackout, connect cables, install a current transformer, connect active power filter to the on-site power distribution system, complete at 23:00 PM, and transmit power after the check is correct.

2.5. Check APF operation, sampling data is consistent with the system actual electrical data, adjust parameter Settings, after debugging, the APF active power filter compensation effect is good, stable, the system harmonic current distortion rate is reduced from about 50%, down to 5%, the dual power switch N phase current has dropped from 250 a to around 27 a, dual power switch position N phase fever phenomenon disappear

2.6. Record the compensated system data and capture the power quality data and waveform.

3. Trust-mart Shopping Mall 0.4KV LT Power Distribution System

4. Analysis of harmonic elimination effect

4.1 Current Data analysis

a.System current waveform

Before the active power filter is turned on, the load current waveform deviates from the sinusoidal waveform. The effective value of the A/B/C three-phase current is about 210A, and the N phase current is about 250A.

After treatment. The effective value of the A/B/C three-phase current drops to about 170A, and the N-phase current drops to about 17A.

b. Total current harmonic distortion rate

Before the active power filter is turned on, the total harmonic current distortion rate of the load current is about 50%, and the main harmonic current distortion orders are 3/5/7/11 harmonic current distortion.

After the active power filter is turned on, the total harmonic current distortion rate of the load current decreases to about 5%, and the number of major harmonic distortions for 3/5/7/9/11 decreases significantly

4.2 Voltage Data analysis

a. System voltage waveform

b.System voltage harmonic distortion rate

Before the active power filter is turned on, the system voltage has slight harmonic distortion, the total harmonic distortion rate is about 2.5%, and the main distortion orders are 3/5/7 harmonic distortion.

After the active power filter is turned on, the harmonic voltage distortion of the system decreases from about 2.5% to 1%, and the harmonic distortion of each time decreases

4.3 Power Factor Analysis

Before APF start, the double power switch downside load power factor is A phase 0.89、B phase 0.86 / C phase 0.85,

After the active power filter equipment start, the double power switch downside load power factor is greatly improved, A phase 0.97、B phase 0.98 、 C phase 0.97, the PF increase ratio is close to 0.1, the system power factor is affected by a large amount of harmonic current.

5. Conclusion

After installing our active power filter (APF), the trust-mart shopping mall 0.4 KV double power switch downside load harmonic current distortion rate has improved significantly, the dual power switch N phase flow of current was reduced from the original 250a to 17a, which greatly guarantee the system security and stability, lower N phase cable heating、insulation aging、and the risk of fire hazard problem.

Before the active filter was installed, there are many 3rd harmonic distortion problems in presence of the system due to the dual power switch downside load of LED lighting, LED display frequency, that equipment, causing a lot of distortion due to 3rd harmonic current, which is superimposed on N phase, this leads to much harmonic current on N phase, it makes N cable heating, the dual power switch tripped due to overheating protection problems, these problems are solved by CoEpower active power filter (APF) and significantly improved.