POWER FACTOR CORRECTION WISEMAN NENE EIT – ELECTRICAL ESTON SUGAR MILL

POWER FACTOR CORRECTION AS A MEANS OF COST SAVINGS

CONTENT INTRODUCTION OBJECTIVES NATURE OF ELECTRICAL POWER/LOAD POWER FACTOR THEORY

ADVANTAGES OF IMPROVED POWER FACTOR DISADVANTAGES OF LOW POWER FACTOR METHODS OF IMPROVING POWER FACTOR OVERVIEW OF THE SYSTEM SYSTEM BREAKDOWN

POWER AND COSTS SAVINGS PROJECT COSTS COSTS RECOVERY PERIOD SAFETY AND MAINTENANCE OF THE SYSTEM CONCLUSION

INTRODUCTION COSTS SAVINGS IS ONE OF THE MEASURE DRIVERS IN INDUSTRY FOR BUSINESS SUSTAINABILITY POWER FACTOR CORRECTION IS ONE OF THE MEANS THAT CAN BE USED TO REDUCE COSTS

NATURE OF ELECTRICAL LOAD Resistive - I and V peaks are simultaneous The angle between the two is zero Inductive - I lags V The angle between the two is negative Capacitive – I leads V The angle between the two is positive

OBJECTIVES TO INVESTIGATE MEANS OF COST REDUCTION FROM THE ELECTRICAL PERSPECTIVE – (POWER FACTOR CORRECTION)

POWER FACTOR THEORY PF = ACTIVE POWER / APPARENT POWER = P / S = kW / kVA ACTIVE POWER (P) = kW APPARENT POWER (S) = kVA

POWER TRIANGLE

SYSTEM BEFORE PFC PF = 0.68 Lagging

DESIRED MINIMUM SYSTEM TRIANGLE PF = 0.8 Lagging

NEW SYSTEM POWER TRIANGLE PF = 0.92 Lagging

ADVANTAGES OF IMPROVED PF REDUCED APPARENT POWER PRODUCED IMPROVED PLANT EFFICIENCY ADDITIONAL LOADS CAN BE ADDED TO THE SYSTEM REDUCED OVERLOADING OF CABLES, TRANSFORMERS, SWITCHGEAR, ETC. IMPROVED NETWORK VOLTAGE IMPROVED STARTING TORQUE OF MOTORS

DISADVANTAGES OF LOW PF INCREASES ELECTRICITY COSTS CAUSES OVERLOADING OF GENERATORS, TRANSFORMERS AND DISTRIBUTION SYSTEM GREATER VOLTAGE DROPS AND POWER LOSSES LOW EFFICIENCY AND UNNECESSARY WEAR AND TEAR TO INDUSTRIAL ELECTRICAL EQUIPMENT REDUCES LOAD HANDLING OF THE PLANTS’ ELECTRICAL SYSTEM

METHODS OF IMPROVING POWER FACTOR SYNCHRONOUS MOTORS STATIC VAR COMPENSATORS STATIC CAPACITORS

METHODS OF IMPROVING POWER FACTOR SYNCHRONOUS MOTORS Has long service life Can withstand higher short circuit currents High maintenance and installation costs STATIC VAR COMPENSATORS Fast response system System is very expensive

STATIC CAPACITORS Simple and easy to install Cannot be repaired

CONNECTION TO THE NETWORK Basic connection diagram for static capacitors

SYSTEM CONFIGURATION 4 x 48kVAr + 3 x 50 kVAr = 342 kVAr FRONT – END SECTION 4 x 48kVAr + 3 x 50 kVAr = 342 kVAr BACK – END SECTION = 6 x 62.5 kVAr = 375 kVAr

SYSTEM OPERATION Manual Mode Uses a selector switch to select a stage Automatic – using Epcos BR6000 PFC Controller Uses a selector switch to automatically select a stage

POWER AND COSTS SAVINGS Electrical saving in terms of the power consumed P = 151.44 kW P = 429.08 kW @ 0.68 PF , S = 631 kVA And at: @ 0.92 PF, S = 466.39 kVA STOTAL = SOLD – SNEW = 164.61 kVA I = S/√3 x 525 = 181.02A P = √3 V I Cos θ = 151.44 kW

RAND VALUE SAVING (ACTUAL) Assuming 24 hours/day for 30 days @ 0.4019/kWh and saving 151.44 kWh, National grid Power Energy Charge Saving = 151.44 x 24 x 30 x 0.4019 = R 43,821.89/month

POWER SAVINGS (BACK-END) P = 903.4 kW @ 0.61 PF, SOLD = 1.48 MVA @ 0.8 PF, SNEW = 1.13 MVA STOTAL= SOLD – SNEW = 350 kVA I = S/√3 x 525 = 384.9 A P = √3 V I Cos θ = 280 kW

SAVINGS ( RAND-VALUE, BACK-END) Assuming 24 hours/day for 30 days @ 0.4019/kWh and saving 280 kW hourly: Energy Charge Saving = 280 x 24 x 30 x 0.4019 = R 81,023.04/month

OVERALL POWER / COST SAVINGS For 2010 season Eskom used during crushing=331.3 hrs, [06-07-10 to 04-10-10] Electrical Power saved; P FRONT-END = 151.44 kW P BACK-END = 280 kW Total Power Saved (2010 season) = 151.44 kW + 280 kW = 431.44 kW = 431.44 kW x 331.3hrs = 142.936 MWh = 142936kWh x R0.4019 /kWh = R 57,446.00

BUDGET & COSTS RECOVERY PERIOD Approximately R45 000. Source: Electrical Department Budget Recoverable: Within 1 Month on National Grid

FINAL SYSTEM PICTURES The following pictures shows the installation locations and the results obtained from the front-end section

CONTROLLER Controller - Epcos BR6000

CONTROL Auto and Manual Control

CAPACITOR BANKS

CONTROL PANELS

MAIN PANELS

DISPLAYS With all banks OFF

WITH 6 BANKS ON .

PF ALL BANKS ON PF = 0.92 Lagging

BACK-END SECTION

SAFETY No unauthorized person should switch the system ON/OFF. Before opening the capacitor banks panels, make sure the main isolator is off and wait for at least 5minutes for the capacitors to discharge

CONCLUSION As seen on the pictures in the previous slides, the new system was successful. The power factor was corrected from 0.68 lagging to 0.92 lagging in the front-end and from 0.61 to 0.8 lagging in the back-end section

CONCLUSION cont. The costs and power savings were significant at 142.936 MWh during the 4 months period recorded during the 2010 season

ACKNOWLEDGEMENTS ESTON ENGINEERING TEAM

THANK YOU!!! ???