Delta's Active Power Filter successfully installed in the world’s largest chemical fiber producer and textile enterprise

Industry background
Major processes in chemical fiber production include polymerization, filament drawing, cooling, and wastewater treatment. The VFD winding machine is the major electrical equipment used in filament drawing. In polymerization, TPA after mixing, heating, and reacting is transferred to the filament workshop through channels. The mixer, centrifuge (VFD), and filter tower are the major pieces of electrical equipment used in polymerization. There are also the HTM furnace and recycled water treatment processes that need VFDs for pumps.
The harmonic content varies from VFD to VFD and from model to model. In filament drawing and wastewater treatment, the total harmonic distortion (THD) of transformers is severe, usually over 25%.

Customer
Hengli Group (World’s largest chemical fiber producer and textile enterprise)

Power quality problem descriptions
The Hengli Group is the world’s largest chemical fiber producer and textile enterprise. Power factor drops in some of the group’s power distribution rooms due to blown or damaged capacitor banks are very common. Production losses are caused from overheated transformers which create a loud noise, the high failure rate of relevant electrical equipment, and abnormally tripping breakers.

Cause analysis
Numerous VFDs generate massive harmonic content of 5th, 7th, 11th, and 13th orders in the current, which causes voltage distortion when flowing through grid system impedance. Voltage distortion exceeds the international standard, damages other electrical devices, and causes resonance with system impedance and capacitor banks, thus damaging capacitors and jeopardizing the grid.

Solution
By referring to onsite conditions and the pilot test and assessment, a Delta PQC series APF with model name of PQCA-400-75-375C4 is thus installed at the secondary side of each of all the 32 distribution transformers in the new factory. The single transformer solution is illustrated below:

Effectiveness
The effectiveness of the PQC active power filer is significant, as shown in the data below:

Current waveform and THD before and after PQC application are shown below:

 

Project conclusions
Delta PQC series APF has demonstrated excellent performance in power quality management for the chemical fiber industry. It significantly enhances distribution system stability, reduces the equipment failure rate, fully releases the distribution margin, enhances production capacity, and saves energy at a certain level. Therefore, it brings tremendous direct and indirect economic value for the long run.

Deployment site