power factor improvement concept for · pdf file4 powerflow technologies inc power factor...

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

http://www.powerflowtechnologies.com/



POWER FACTOR REQUIREMENTS FOR A POWER FACTOR REQUIREMENTS FOR A MODERN PLANTMODERN PLANT



WHAT IS POWER FACTOR ?WHAT IS POWER FACTOR ?



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)



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



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



METHODS FOR IMPROVING POWER FACTORMETHODS FOR IMPROVING POWER FACTOR

CAPACITOR BANKS

SYNCHRONOUS MOTORS



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




Apparent power

kVA

W:

Active power

kWQ:

Reactive

kVar

P:

Mechanical power

kW

Vector DiagramOA:



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



OPEN CAPACITOR BANK INSTALLATIONOPEN CAPACITOR BANK INSTALLATION



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)



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



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




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



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:



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



SYNCHRONOUS MOTOR WITH VARIABLE SPEED FLUID COUPLING



SYNCHRONOUS MOTOR

WITH CONTROLLED FILL FLUID COUPLING 8200 HP ID FAN



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



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



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



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



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.



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



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



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



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



ENDEND

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