1. Project Overview
This is a chemical plant with a lot of high-power water pump equipment, and a large number of frequency converters are installed for water pump control.
These frequency converters have caused serious harmonic problem in the system. The harmonic distortion rate has reached 35%, which seriously affects the safe and stable operation of the system. It is urgent to carry out harmonic control, to improve the power grid environment, and avoid safety hazards.
2. Distribution system diagram and main harmonic loads
There are two 10/0.4KV transformers on site, the main load is the water pump, and the main harmonic source is the high-power frequency converters.
3. Harmonic mitigation solution
It is designed to install a 400A active power filter at the downstream of two transformers on site to control the harmonic current.
Due to limited installation space and budget of the customer, the newly added active power filter cabinet at the downstream of the II-stage transformer is suggested to be installed using the equivalent load side connection method.
Equipment Selection: Active Power Filter (APF)
Equipment model: CoEpo APF/400-0.4-D
Management method: bus centralized management
Installed capacity: 800A
Installation method: rack type
Installation location: power distribution room
4. Effect
The main harmonic orders are the 5th and 7 th harmonics, and the current waveform presents a typical double-headed waveform. Before the treatment, the total harmonic distortion rate of the system reached 35.8%. After the treatment, the wave distortion rate dropped to about 5%, the waveform returned to normal, and each harmonic dropped significantly.
The main harmonic orders are the 5th and 7 th harmonics, and the current waveform presents a typical double-headed waveform. Before the treatment, the total harmonic distortion rate of the system reached 32.8%. After the treatment, the wave distortion rate dropped to about 5%, the waveform returned to normal, and each harmonic dropped significantly.
