: Chemical Manufacturing Unit.
: The Manufacturing plant of a Chemical Multinational Company in Roha got a Notice from MSEDCL for control of Harmonic percentage as per IEEE 519-1992. The utility company had recorded higher percentage of Current Harmonic Distortion at the PCC & threatened with disconnection of supply if compliance was not achieved in stipulated time duration.
The facility receives Electrical input through 22kV/433V, 2MVA transformer. 100kVAR fixed Capacitor Banks are used for Reactive Power Compensation. On a typical working day kWh consumption is around 2800 to 3000 units. The load is contributed of Motors and VFD’s.
A detailed Power Quality audit for the facility was recommended. The data was to be collected at multiple points starting from the Transformer Secondary till MCC. A 24Hr data collection of power parameters was conducted at Transformer level.
Observation & Problem Identification:
The current harmonics distortion was recorded at 30% with Capacitor bank ON, it was observed at 17% when Capacitor bank was OFF. The permissible limit for the facility was 15% only as per IEEE norms. Predominant Harmonics were 5th, 7th, 11th, 13th, & 19th. The Harmonic distortion was load generated & was getting amplified by the fixed reactive compensation from the Capacitors installed.
Parameters to be achieved:
- To reduce Current Harmonics Distortion and enhance the quality of Power within the distribution.
- Achieve Unity PF for all load conditions assuring them Incentive from the utility company.
- Comply IEEE-519-1992 Standards as demanded by the utility company.
Considering the above parameters & in order to achieve the necessary results we recommended Hybrid Solution to meet all requirements. A de-tuned Filter with Thyristor fired Controller for pF Correction and mitigates 5th & 7th Harmonics. To mitigate the remaining Harmonic band, we suggested an Active Harmonic Filter Panel at PCC. This reduced the Capital Investment for Client.
- 225kVAR De-tuned Filter with Thyristor Fired Controller.
- 60A Active Harmonic Filter.
The 225kVAR Detuned Filter and 60A Active Filter was installed as per SLD provided and the readings were taken to see the results achieved.
Benefit to the Client:
- 225kVAR Detuned Filter compensated required reactive Power without amplifying load generated harmonics. The Harmonics percentage was brought down to 17% from 30% maintaining Unity PF.
- 60A Active Filter mitigates the remaining Harmonic band and to reduced iTHD to 6% from 17%.
- Before Implementation (Fig 1), After Implementation (Fig, 2)
- Solution Implemented in Lower CAPEX.
- Compliance to IEEE-519 (1992) Standards as required by the Utility Company.
- Enhance the Quality of Power, Capacitor Life.
- Instantaneous and Step less Correction for p.F and Harmonics Mitigation.
- Maintain Unity p.F at any given moment and load condition. Assured Incentive from the Utility Company.
- Release of Power in kVA from the same utility transformer.
- Enhanced Life of LT Cables, Switchgears and Transformer.