1Powerflow Technologies Inc
Power factor correction
POWER FACTOR IMPROVEMENT CONCEPTPOWER FACTOR IMPROVEMENT CONCEPT FOR LARGE MOTORSFOR LARGE MOTORS
POWERFLOW TECHNOLOGIES POWERFLOW TECHNOLOGIES IncInc
4031 FAIRVIEW ST, Burlington,Ontario, CANADA, L7L4031 FAIRVIEW ST, Burlington,Ontario, CANADA, L7L--2A42A4
905905--336 2686, 336 2686, www.powerflowtechnologies.com
2Powerflow Technologies Inc
Power factor correction
POWER FACTOR REQUIREMENTS FOR A POWER FACTOR REQUIREMENTS FOR A MODERN PLANTMODERN PLANT
4Powerflow Technologies Inc
Power factor correction
POWER FACTOR CONCEPTPOWER FACTOR CONCEPT
1.1.
THE UTILITY IS REQUIRED TO SUPPLY POWER THE UTILITY IS REQUIRED TO SUPPLY POWER (kVA)(kVA)
THAT THAT INCLUDES A COMPONENT OF REACTIVE POWER INCLUDES A COMPONENT OF REACTIVE POWER (kVAr)(kVAr)
AND A COMPONENT OF REAL POWER AND A COMPONENT OF REAL POWER (kW)(kW)
2.2.
THE REAL POWER THE REAL POWER (kW)(kW)
IS WHAT IS ABSORBED BY THE IS WHAT IS ABSORBED BY THE LOAD AND DISSIPATED AS ELECTRICAL HEAT LOSES.LOAD AND DISSIPATED AS ELECTRICAL HEAT LOSES.
3.3.
THE REACTIVE POWER THE REACTIVE POWER (kVAr)(kVAr)
IS REQUIRED BY THE IS REQUIRED BY THE MAGNETIC CIRCUIT TO PRODUCE TORQUE (MOTOR) OR MAGNETIC CIRCUIT TO PRODUCE TORQUE (MOTOR) OR INDUCE VOLTAGE (TRANSFORMER)INDUCE VOLTAGE (TRANSFORMER)
5Powerflow Technologies Inc
Power factor correction
POWER FACTOR CONCEPTPOWER FACTOR CONCEPT
THE APPARENT POWER THE APPARENT POWER (kVA)(kVA)
SUPPLIED BY THE UTILITY IS SUPPLIED BY THE UTILITY IS THE RESULT OF THE QUADRATIC SUM GIVEN BY THE THE RESULT OF THE QUADRATIC SUM GIVEN BY THE FOLLOWING EQUATIONFOLLOWING EQUATION
kVA = [kW ²
+ kVAr ²]½
THE POWER FACTOR (PF)
IS THE VALUE OF THE COSINE OF THE ANGLE Φ
RESTING BETWEEN THE VECTORS DEFINING THE ACTIVE POWER AND THE APPARENT POWER
PF=COS Ф=kW : kVA
6Powerflow Technologies Inc
Power factor correction
Typical Power Flow in Motor CircuitS:
Apparent power
kVA
W:
Active power
kWQ:
Reactive
kVar
P:
Mechanical power
kWVector DiagramOA:
Active power W (kW)OB:
Inductive reactive power Q (kVar)OC:
Apparent power s (kVA)CD: Leading reactive power
compensation Q’: (kVar)Φ:
Phase angle uncompensatedΦ’:
Phase angle compensatedW
B
Q
O
Q’
A
SS’
Φ
Φ’
C
D
Generator
MInduction
Motor
G PS
POWER FACTOR IMPROVEMENT CONCEPT
WQ
UNCOMPENSATED MOTOR CIRCUIT
7Powerflow Technologies Inc
Power factor correction
METHODS FOR IMPROVING POWER FACTORMETHODS FOR IMPROVING POWER FACTOR
CAPACITOR BANKS
SYNCHRONOUS MOTORS
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Power factor correction
POWER FACTOR IMPROVEMENT USING POWER FACTOR IMPROVEMENT USING CAPACITORSCAPACITORS
FEATURESFEATURES
BUILDING BLOCKS OF STANDARD kVAR units to desired capacityBUILDING BLOCKS OF STANDARD kVAR units to desired capacityCOULD BE SWITCHED IN BANKS AT MCC WITH POWER FACTOR COULD BE SWITCHED IN BANKS AT MCC WITH POWER FACTOR CONTROLLER OR WITH THE INDIVIDUAL INDUCTION MOTOR CONTROLLER OR WITH THE INDIVIDUAL INDUCTION MOTOR TYPICALLY APPLIED IN LOW VOLTAGE CIRCUITS (380 TYPICALLY APPLIED IN LOW VOLTAGE CIRCUITS (380 ––690V)690V)MORE EXPENSIVE FOR MEDIUM VOLTAGE (3.8kV MORE EXPENSIVE FOR MEDIUM VOLTAGE (3.8kV –– 6.9kV)6.9kV)DEPENDING ON THE SIZE OIL CONTAINMENT IS REQUIRED & ENCLOSURESDEPENDING ON THE SIZE OIL CONTAINMENT IS REQUIRED & ENCLOSURESFLAMMABLE DIELECTRIC FLAMMABLE DIELECTRIC REQUIRE FILTER REACTORS TO DEREQUIRE FILTER REACTORS TO DE--TUNE HARMONIC FREQUENCIESTUNE HARMONIC FREQUENCIESVULNERABLE TO SWITCHING SURGES VULNERABLE TO SWITCHING SURGES COMPENSATION LIMITED TO 0.95 LAGGING POWER FACTOR DUE TO COMPENSATION LIMITED TO 0.95 LAGGING POWER FACTOR DUE TO OVEREXCITATION AND SWITCHING RESONANCE.OVEREXCITATION AND SWITCHING RESONANCE.kVAR OUTPUT kVAR OUTPUT ~ (TERMINAL VOLTAGE)~ (TERMINAL VOLTAGE)--½½
9Powerflow Technologies Inc
Power factor correction
Typical Power Flow in Motor CircuitS:
Apparent power
kVA
W:
Active power
kWQ:
Reactive
kVar
P:
Mechanical power
kW
Vector DiagramOA:
Active power W (kW)OB:
Inductive reactive power Q (kVar)OC:
Apparent power S (kVA)CD: Capacitor reactive power Q’: (kVar)Φ:
Phase angle uncompensatedΦ’:
Phase angle compensatedOD:
New apparent power from utility S’W
B
Q
O
Q’
A
SS’
Φ
Φ’
C
D
UTILITY Generator
MInduction
Motor
G PWQ
SS’
Q’ Capacitor Bank & FILTER
POWER FACTOR CORRECTION USING CAPACITORS
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Power factor correction
OPEN CAPACITOR BANK INSTALLATIONOPEN CAPACITOR BANK INSTALLATION
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Power factor correction
POWER FACTOR IMPROVEMENT USING SYNCHRONOUS MOTORS
SYNCHRONOUS MOTORS WITH UNITY POWER FACTOR (PF=1.0)
SYNCHRONOUS MOTORS WITH LEADING POWER FACTOR –OVEREXCITED (PF= 0.9 –0.8 LEADING)
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Power factor correction
IMPROVING POWER FACTOR USING IMPROVING POWER FACTOR USING SYNCHRONOUS MOTORSSYNCHRONOUS MOTORS
FEATURESFEATURESDYNAMICALLY COMPENSATES AND IMPROVES POWER FACTOR AND DYNAMICALLY COMPENSATES AND IMPROVES POWER FACTOR AND VOLTAGE LEVELS AS DICTATED BY THE PLANT LOADVOLTAGE LEVELS AS DICTATED BY THE PLANT LOADREACTIVE COMPENSATION PROPORTIONAL WITH DC EXCITATION REACTIVE COMPENSATION PROPORTIONAL WITH DC EXCITATION LEVELLEVELUNITY OR LEADING POWER FACTOR CAPABILITIES WHICH COULD BE UNITY OR LEADING POWER FACTOR CAPABILITIES WHICH COULD BE USED TO COMPENSATE THE ENTIRE PLANT POWER SYSTEMUSED TO COMPENSATE THE ENTIRE PLANT POWER SYSTEMCAN RUN DECOUPLED AS A SYNCHRONOUS CONDENSER (Requires a CAN RUN DECOUPLED AS A SYNCHRONOUS CONDENSER (Requires a Fluid Coupling or an Air Clutch to DeFluid Coupling or an Air Clutch to De--Clutch from the Driven Machine)Clutch from the Driven Machine)REQUIRES LITTLE MAINTENANCE REQUIRES LITTLE MAINTENANCE -- BRUSHLESS EXCITERSBRUSHLESS EXCITERSMOST ECONOMICAL FOR PLANT INSTALLATIONS REQUIRING MOST ECONOMICAL FOR PLANT INSTALLATIONS REQUIRING SIGNIFICANT PF COMPENSATIONSIGNIFICANT PF COMPENSATIONMOST ECONOMICAL FOR 2000 kW AND LARGER LOADSMOST ECONOMICAL FOR 2000 kW AND LARGER LOADSOUTPUT PROPORTIONAL WITH TERMINAL VOLTAGEOUTPUT PROPORTIONAL WITH TERMINAL VOLTAGELOW STARTING CURRENT INRUSH AND LOW TORQUE REQUIREMENTS LOW STARTING CURRENT INRUSH AND LOW TORQUE REQUIREMENTS WHEN COUPLED WITH CONTROLLED FILLED FLUID COUPLINGS or Air WHEN COUPLED WITH CONTROLLED FILLED FLUID COUPLINGS or Air ClutchClutch
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Power factor correction
SYNCHRONOUS MOTOR APPLICATIONSYNCHRONOUS MOTOR APPLICATION
1.
BALL MILLS –
WITH CONTROLLED FILL FLUID COUPLING or Air clutch
2.
INDUCED DRAFT FANS WITH OR WITHOUT SPEED CONTROL –WITH CONTROLLED FILL FLUID COUPLING
3.
VERTICAL MILLS WITH HYDRAULIC LIFTERS (LOESCHE, FLS, KHD, ETC) –
DIRECT COUPLED
4.
VERTICAL MILLS WITHOUT HYDRAULIC LIFTERS –
WITH CONTROLLED FILL FLUID COUPLING or cycloconverter (POLYSIUS, PFEIFFER, Etc, High starting and breakdown torques)
5.
SAG mills, Ball mills, high starting current high torque
6.
Large MG sets 0.8 leading power factor
14Powerflow Technologies Inc
Power factor correction
Typical Power Flow in Motor CircuitS:
Apparent power
kVA
W:
Active power
kWQ:
Reactive
kVar
P:
Mechanical power
kW
UTILITY Generator
MSYNCHRONOUS
Motor
G PWQ
S’
POWER FACTOR CORRECTION USING SYNCHRONOUS MOTORS
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Power factor correction
S
S’= S
Q
O
A
BC
S’
= W, Φ=0º, COS’
Φ
= 1
Φ’=0º
Φ’= 30º
D
POWER FACTOR IMPROVEMENT USING SYNCHRONOUS MOTOR WITH UNITY AND LEADING POWER FACTOR
EVector Diagram
OA:
Active power W (kW)OB:
Inductive reactive power Q (kVar)OC:
Apparent power S (kVA)CD: Reactive power compensation Q’: (kVar) for unity PFΦ’:
Phase angle compensatedOD:
New apparent power from utility S’
at unity PFAE:
Equivalent leading PF capacitor bank replaced = 25% of nameplate kVA of motor to compensate the balance of plant. Machine kVA S’
= S.
S’=S,
Φ=-30º,
COS Φ
= .8
W
16Powerflow Technologies Inc
Power factor correction
SYNCHRONOUS MOTOR WITH VARIABLE SPEED FLUID COUPLING
17Powerflow Technologies Inc
Power factor correction
SYNCHRONOUS MOTOR
WITH CONTROLLED FILL FLUID COUPLING 8200 HP ID FAN
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Power factor correction
5400 kW BALL MILL DRIVE WITH SYNCHRONOUS MOTOR 5400 kW BALL MILL DRIVE WITH SYNCHRONOUS MOTOR and CONTROLLED FILLED FLUID COUPLINGand CONTROLLED FILLED FLUID COUPLING
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Power factor correction
APPLICATION EXAMPLE APPLICATION EXAMPLE --AA
Option 1Option 1PREHEATER ID fan with VFD + Induction MotorPREHEATER ID fan with VFD + Induction Motor
Option 2Option 2PREHEATER ID fan with Synchronous motor with PREHEATER ID fan with Synchronous motor with controlled fill variable speed fluid coupling controlled fill variable speed fluid coupling
20Powerflow Technologies Inc
Power factor correction
INVESTMENT COST ANALYSIS INVESTMENT COST ANALYSIS --EXAMPLE A EXAMPLE A -- 5000HP, 890 RPM PREHEATER ID FAN DRIVE5000HP, 890 RPM PREHEATER ID FAN DRIVE
OPTION 1OPTION 1 OPTION2OPTION2 Speed control range Speed control range --15%, max 15%, max --34%34%
MOTORMOTOR $447,000$447,000 Synch Motor 0.8 Synch Motor 0.8 lead PFlead PF
$685,000$685,000
TransformerTransformer $190,000$190,000 Fluid CouplingFluid Coupling $375,000$375,000
VFDVFD $640,000$640,000 Water CoolingWater Cooling $40,000$40,000
SwitchgearSwitchgear $165,000$165,000 SwitchgearSwitchgear $80,000$80,000
Elec RoomElec Room $275,000$275,000 Elec roomElec room $50,000$50,000
Capacitor bankCapacitor bank $167,000$167,000 Not requiredNot required NilNil Equivalent Equivalent correctioncorrection
Total costTotal cost $1,884,000$1,884,000 Total CostTotal Cost $1,230,000$1,230,000 DIFFERENCEDIFFERENCE$654,000 $654,000
21Powerflow Technologies Inc
Power factor correction
DRIVE TRAIN EFFICIENCY ANNALYSISDRIVE TRAIN EFFICIENCY ANNALYSIS--
EXAMPLE A EXAMPLE A 5000 HP, 890 RPM, PREHEATER ID FAN DRIVE TRAIN5000 HP, 890 RPM, PREHEATER ID FAN DRIVE TRAIN
OPTION 1OPTION 1 Efficiency %Efficiency % OPTION 2OPTION 2 Efficiency%Efficiency% 15% speed 15% speed changechange
Induction MotorInduction Motor 95.6 @ 60Hz 95.6 @ 60Hz --
51Hz51Hz
Synchronous Synchronous Motor (actual Motor (actual 98.1%)98.1%)
97.4@60Hz min 97.4@60Hz min guaranteedguaranteed
TransformerTransformer 99.1@60 Hz99.1@60 Hz N/AN/A N/AN/A
VFD ElectronicsVFD Electronics 9898 Fluid coupling Fluid coupling slip2.5% @100%slip2.5% @100%1.3% @85%1.3% @85%
97.5 @100 97.5 @100 speed speed 98.7@85%speed98.7@85%speed
Filter lossFilter loss1500kVAr 1500kVAr --1%1%
99.6 99.6 N/AN/A N/AN/A
Drive train Drive train EfficiencyEfficiency
92.47 @ 60Hz92.47 @ 60Hz--
51Hz51Hz
Drive train Drive train efficiencyefficiency
[email protected]@100% % 96.13@85% 96.13@85% speedspeed
AVG 87.22kW, AVG 87.22kW, 8250hrs/year/$0.8250hrs/year/$0.
055/kwhr055/kwhr
$39,576 annual $39,576 annual savingssavings
Efficiency gain Efficiency gain 2.43%,2.43%,3.66% @85%3.66% @85%
90.6kW@100%90.6kW@100%83.84kW@85%83.84kW@85%87.22kw average87.22kw average
22Powerflow Technologies Inc
Power factor correction
APPLICATION EXAMPLE A APPLICATION EXAMPLE A --5000HP PREHEATER ID FAN DRIVE 5000HP PREHEATER ID FAN DRIVE SYSTEMSYSTEM
OPTION 2 ADVANTAGES
1.
Lower initial capital cost by $654,000
2.
Higher operating efficiency –savings in electrical energy of $39,576/year.
3.
Lower maintenance and fewer components
4.
Higher reliability resulting in higher OEE particularly of PREHEATER application
5.
Lower clinker cost factor in this application
6.
Dynamic power factor compensation and voltage stability to the rest of the plant by virtue of the leading power factor.
23Powerflow Technologies Inc
Power factor correction
APPLICATION EXAMPLE APPLICATION EXAMPLE --BB
Cement plant with 40 MVA demand 0.85 pf, equivalent 34 MW POWER Cement plant with 40 MVA demand 0.85 pf, equivalent 34 MW POWER DEMAND. DEMAND. NEED TO BE CORRECTED TO 0.95 PF LAG.NEED TO BE CORRECTED TO 0.95 PF LAG.
MAIN EQUIPMENT; 6200HP, 900 RPM RAW MILL, 5000HP, 900 RPM ID FANMAIN EQUIPMENT; 6200HP, 900 RPM RAW MILL, 5000HP, 900 RPM ID FAN, , 2X5400HP 1200RPM BALL MILS2X5400HP 1200RPM BALL MILS
OPTION 1OPTION 1-- USE SLIP RING MOTORS WITH POWER FACTOR CORRECTION USE SLIP RING MOTORS WITH POWER FACTOR CORRECTION CAPACITORSCAPACITORS
OPTION 2OPTION 2-- USE SYNCHRONOUS MOTORS WITH FLUID COUPLING, UNITY USE SYNCHRONOUS MOTORS WITH FLUID COUPLING, UNITY POWER FACTOR MOTORSPOWER FACTOR MOTORS
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Power factor correction
APPLICATION EXAMPLE B APPLICATION EXAMPLE B --
40MVA, 0.85 lag PF PLANT DEMAND, 40MVA, 0.85 lag PF PLANT DEMAND, 2X5400HP, 1200 rpm BALL MILL DRIVES, compensate to 0.95 lag2X5400HP, 1200 rpm BALL MILL DRIVES, compensate to 0.95 lag
OPTION1OPTION1 SLIP RING MOTORS SLIP RING MOTORS RHEOSTAT: 6200hp RHEOSTAT: 6200hp raw mill, 5000hp RM fanraw mill, 5000hp RM fan2x5400hp ball mills2x5400hp ball mills
OPTION2OPTION2 SYNCHRONOUS SYNCHRONOUS MOTOR, 1.0 PFMOTOR, 1.0 PF6200hp raw mill, 6200hp raw mill, 5000hp RM fan, 5000hp RM fan, 2x5400hp ball mills2x5400hp ball mills
Ball mill motorsBall mill motors 2x$397,000=$794,0002x$397,000=$794,000 Ball mill motors Ball mill motors 2x$360,000=$720,0002x$360,000=$720,000 All $US dollarsAll $US dollars
Raw mill motor Raw mill motor 1x$415,000=$415,0001x$415,000=$415,000 Raw mill motorsRaw mill motors 1x$390,000=$390,0001x$390,000=$390,000
Raw Mill ID fanRaw Mill ID fan 1x$420,000=$420,0001x$420,000=$420,000 Raw Mill ID fanRaw Mill ID fan 1x$375,000=$375,0001x$375,000=$375,000
Capacitor filter bank and Capacitor filter bank and switchgear to 0.95 PFswitchgear to 0.95 PF3x1500kVar,3x1500kVar,1x2000kVar1x2000kVar
3x$28,000=$84,0003x$28,000=$84,0001x$31,000=$31,0001x$31,000=$31,000
Fluid coupling 1.8% slipFluid coupling 1.8% slip 4x$180,000=$720,0004x$180,000=$720,000
Capacitor bank for the Capacitor bank for the remainder of the plantremainder of the plant10000kVAr 10000kVAr --6,500kVar=6,500kVar=3,500kVar3,500kVar
1x$45,000=$45,0001x$45,000=$45,000 With unity power factor With unity power factor synch motors the plant synch motors the plant operates at 95.2PF. operates at 95.2PF.
Leading PF SYN motors Leading PF SYN motors not needed.not needed.
Total Equipment costTotal Equipment cost $1,789,000$1,789,000 $2,205,000$2,205,000 Difference in initial Difference in initial investment cost investment cost $416,000$416,000
25Powerflow Technologies Inc
Power factor correction
APPLICATION B APPLICATION B ––
40MVA PLANT CORRECTED TO 40MVA PLANT CORRECTED TO 0.95 PF= 35.78MVA DEMAND FROM UTILITY0.95 PF= 35.78MVA DEMAND FROM UTILITY
OPTION 1OPTION 1 EFFICIENCYEFFICIENCY OPTION 2OPTION 2 EFFICIENCYEFFICIENCY
BALL MILL MOTORSBALL MILL MOTORS 0.9450.945 SYNCH MOTORS SYNCH MOTORS BALL MILLBALL MILL
0.981 x.982= 0.96330.981 x.982= 0.9633
RAW MILL MOTORRAW MILL MOTOR 0.9450.945 RAW MILL MOTOR RAW MILL MOTOR 0.978x0.982=0.9600.978x0.982=0.960
RAW MILL ID FANRAW MILL ID FAN 0.9450.945 RAW MILL ID FANRAW MILL ID FAN 0.978x0.982=0.9600.978x0.982=0.960
CAPACITORS 10,000 CAPACITORS 10,000 MVAR@99%EFFMVAR@99%EFF
0.99720.9972 FLUID COUPLING FLUID COUPLING @1.8% [email protected]% slip
0.9820.982
OVERALL MAIN OVERALL MAIN DRIVES ELECTRICAL DRIVES ELECTRICAL EFFICIENCYEFFICIENCY
0.9420.942 OVERALL EFFICIENCYOVERALL EFFICIENCY 0.96110.9611 THE EQUIVALENT THE EQUIVALENT OPERATING OPERATING EFFICIENCY IS EFFICIENCY IS HIGHER USING THE HIGHER USING THE SYNCH MOTORS AND SYNCH MOTORS AND FLUID COUPLINGSFLUID COUPLINGS
AVG operating 8250hrs AVG operating 8250hrs per year per year ––cost of cost of electricityelectricity$0.055/kwh$0.055/kwh
$142,232 electrical $142,232 electrical energy savings per year energy savings per year using synchronous using synchronous motors.motors.
Payback in 2.9 yearsPayback in 2.9 years DIFFERENCE IS 1.91% DIFFERENCE IS 1.91% OR 313.46kW per hour OR 313.46kW per hour in favor of synch motors in favor of synch motors
26Powerflow Technologies Inc
Power factor correction
APPLICATION B APPLICATION B ––
40MVA PLANT40MVA PLANT
OPTION 2 OPTION 2 --
ADVANTAGE ADVANTAGE
1.91% higher operating efficiency 1.91% higher operating efficiency ––savings in electrical energy of savings in electrical energy of $142,200 per year.$142,200 per year.Lower maintenance and fewer components, no brushes to replace.Lower maintenance and fewer components, no brushes to replace.Higher reliability resulting in higher OEE particularly nor brusHigher reliability resulting in higher OEE particularly nor brush and h and collector issues.collector issues.Lower clinker cost factor in this application.Lower clinker cost factor in this application.Dynamic power factor compensation and voltage stability to the rDynamic power factor compensation and voltage stability to the rest est of the plant by virtue of the leading power factor.of the plant by virtue of the leading power factor.Lower real estate required than for slip ring motor Lower real estate required than for slip ring motor Payback in 2.9 years at current energy rates. Demand $ not incluPayback in 2.9 years at current energy rates. Demand $ not included ded
DisadvantageDisadvantageHigher initial operating cost by $416,000Higher initial operating cost by $416,000