Harmonic Mitigation Solution
Pharmaceutical Industry: Jiangsu Taikang Biopharmaceutical Co., Ltd.
Case Introduction:The company's power system had excessive harmonics, affecting the normal operation of equipment and causing communication interruption between the HMI and PLC.
On-site Test Results:The detected harmonic currents are all quite large, with current distortion rates reaching 35% to 45%. Harmonics can affect other loads under the same transformer, especially causing malfunctions or communication interruptions to precision control instruments.
Test location: Main incoming line terminal of AC-CHP cabinet
|
Harmonic current trend |
|
Harmonic current distribution |
|
Current waveform |
List of harmonic currents |
|
Current distortion rate |
Voltage distortion rate |
Test location: Main incoming line terminal of AN501 cabinet
|
Harmonic current trend |
|
Harmonic current distribution |
|
Current waveform |
List of harmonic currents |
|
Current distortion rate |
Voltage distortion rate |
Test location: Main incoming line terminal of AN601 cabinet
|
Harmonic current trend |
|
Harmonic current distribution |
|
Current waveform |
List of harmonic currents |
|
Current distortion rate |
Voltage distortion rate |
Solution:Based on the actual site conditions, the first floor is a rented public transformer, which should not be altered without authorization. Considering the available space, it is recommended to use a wall-mounted APF for on-site treatment. In addition, to eliminate high-frequency harmonics and electromagnetic interference, it is recommended to install a filter at the PLC power supply input terminal.
Photos Of The Mitigation Equipment Installation:
Comparison Of Mitigation Data:
Location：AN601
|
|
|
|
Before mitigation: The three-phase current waveforms were distorted. |
After mitigation: The three-phase current waveform tends to be sinusoidal. |
|
|
|
|
Before mitigation: Total current distortion rate was approximately 35%. |
After mitigation: Total current distortion rate is approximately 8%. |
|
|
|
|
Before mitigation: Phase A fundamental current content: 170.93A Phase A 5th harmonic current content: 55.04A Phase A 7th harmonic current content: 13.44A Phase A 11th harmonic current content: 18.1A
|
After mitigation: Phase A fundamental current content 172.63A Phase A 5th harmonic current content 6.41A Phase A 7th harmonic current content 2.25A Phase A 11th harmonic current content 2.47A
|
Location：AN501
|
|
|
|
Before mitigation: The three-phase current waveforms were distorted. |
After mitigation: The three-phase current waveform tends to be sinusoidal. |
|
|
|
|
Before mitigation: Total current distortion rate was approximately 42%. |
After mitigation: Total current distortion rate is approximately 8%. |
|
|
|
|
Before mitigation: Phase B fundamental current content: 90.52A Phase B 5th harmonic current content: 33.75A Phase B 7th harmonic current content: 14.35A Phase B 11th harmonic current content: 6.75A
|
After mitigation: Phase B fundamental current content 91.07A Phase B 5th harmonic current content 4.21A Phase B 7th harmonic current content 1.95A Phase B 11th harmonic current content 0.59A
|
Location：AC-CHP
|
|
|
|
Before mitigation: The current waveform was distorted. |
After mitigation: The current waveform tends to be sinusoidal. |
|
|
|
|
Before mitigation: Total current distortion rate was approximately 42%. |
After mitigation: Total current distortion rate is approximately 10%. |
|
|
|
|
Before mitigation: Phase C fundamental current: 118.89A Phase C 5th harmonic current: 43.71A Phase C 7th harmonic current: 18.36A Phase C 11th harmonic current: 8.70A
|
After mitigation: Phase C fundamental current: 119.79A Phase C 5th harmonic current: 6.94A Phase C 7th harmonic current: 3.18A Phase C 11th harmonic current: 1.98A
|
Mitigation Result:The harmonics were effectively controlled, and communication between the HMI and PLC returned to normal.