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Power System Harmonic Mitigation for Water/Wastewater Applications

Power Quality Correction

Ben Banerjee

Sept. 30 & Oct. 2, 2008


BenefitsBenefitsFor Harmonics MitigationFor Harmonics Mitigation

For Water & Waste Water ApplicationsFor Water & Waste Water Applications

•• Improved Bottom LineImproved Bottom Line::* System Cost Reduction* System Cost Reduction* Maximize System Reliability* Maximize System Reliability* Improve Energy Efficiency* Improve Energy Efficiency* System Capacity Release* System Capacity Release


Agenda* Characteristic of a Typical W/WW Facility* Impact of Non-Linear Loads* Harmonics Fundamental* Effects of Harmonics* Harmonics Standard IEEE 519-1992 * Cost-Effective Harmonics Mitigations* AccuSine Solutions* Application Considerations


Distribution System/ Load CharacteristicsOf

A Typical W/WW Facility

Division - Name - Date - Language 6

Wastewater PlantsMany pumps for fluid movement (VFD)

– VT– Centrifugal pumps

– CT– Progressive cavity pumps (semi-solids)

Solids handling (VFD)– Conveyors

Aeration blowers (VFD)– CT & VT types

Disinfectant – UV systems (ultraviolet)

– Electronic ballasts – 3Φ– Ozone generators (SCR power supplies)

HVAC

Typical W/WW Applications / Loads


Water PurificationMany pumps (VFD)UV systems (electronic ballasts)Reverse osmosis

– Centrifugal pumps (VFD)Ozone generators (SCR power supplies)

Typical W/WW Applications / Loads


Elect. Loads& System CharacteristicsFor Typical W/WW Facility

> Mostly Motor Loads* Typically 40% to 50% FVNR (Linear Loads)* Typically 30% to 40% VFDs (Non-Linear Loads)* Typically 5% to 10% RVSS

MCC / SWGR/ SWBR Fed Either From Utility Or GeneratorVFDS may be within MCC or remote located

> Generator Normally Sized for Critical Loads> For Water/ Waste Water Facility:

* Sometime UV System (Non-Linear Loads)* Sometime Ozone Generator ( Non-Linear Loads)


Harmonics FundamentalsHarmonics Fundamentals


v i

Until recently, most electrical equipment Until recently, most electrical equipment drew current in a drew current in a ““linearlinear”” fashion:fashion:

Today, many electrical loads draw Today, many electrical loads draw current in acurrent in a““nonnon--linearlinear”” fashion:fashion:

• Current (i) is periodic, but not “sinusoidal”v i

• Current (i) & Voltage (v) are both “Sinusoidal”

Linear vs NonLinear vs Non--LinearLinear


What produces What produces ““NonNon--linearlinear”” Current?Current?

• Computers

• Fax Machines

• Copiers

M • Variable Frequency Drives

• ElectronicBallasts

• Almost Anything Power Electronics

ExamplesExamples


D isto rted Wave =f1 + f3 + f5 + f7

0

0.5

1

1 3 5 7 9 1 1

0

0.5

1

1 3 5 7 9 1 1

0

0.5

1

1 3 5 7 9 1 1

0

0.5

1

1 3 5 7 9 1 1

0

0.5

1

1 3 5 7 9 1 1

f1 = 60 H z

f3 = 3 x 60hz =180 hz

f5 = 5 x 60 hz =300 hz

f7 = 7 x 60 hz =420 hz

f1

f3+

f5+

f7+

=

60 Hz

180 Hz

300 Hz

420 Hz

Time Domain Frequency Domain

All Periodic Waves Are Generated With Sine Waves Of Various FreqAll Periodic Waves Are Generated With Sine Waves Of Various Frequenciesuencies

Now We Can Define Harmonics:

– A harmonic is a component of a periodic wave having a frequency that is an integer multiple of the fundamental power line frequency [ In USA , 60Hz]

• Characteristic harmonics are the predominate harmonics seen by the power distribution system

– Predicted by the following equation:• hC = characteristic harmonics to be

expected• n = an integer from 1,2,3,4,5, etc.• p = number of pulses or rectifiers in

circuit

For Six Pulse Drive:

Harmonic FrequencySequence

1 60Hz

5 300Hz

7 420Hz

11 660Hz

13 780Hz

Fundamental

3rd Harmonic

5t1h Harmonic

7th Harmonic

Hc = np +/- 1

Multi-pulse ConvertersHarmonic Orders Present

Hn1 phase 4-pulse

2 phase 4-pulse

3 phase 6-pulse

3 phase 12-pulse

3 phase 18-pulse

3 x x5 x x x7 x x x9 x x11 x x x x13 x x x x15 x x17 x x x x19 x x x x21 x x23 x x x x25 x x x x27 x x29 x x x31 x x x33 x x35 x x x x x37 x x x x x39 x x41 x x x43 x x x45 x x47 x x x x49 x x x x

Harmonics present by rectifier designType of rectifier

Hn = NP +/- 1

Hn = harmonic order present

N,n = an integer

P = number of pulses


Issues With High System HarmonicsIssues With High System Harmonics

•• System ReliabilitySystem Reliability•• Energy EfficiencyEnergy Efficiency•• System Capacity System Capacity


““KK”” Factor Rated TransformerFactor Rated TransformerFor Dry Type Transformer, To For Dry Type Transformer, To Determine What Amount Of Harmonic Determine What Amount Of Harmonic Current Can Be Tolerated, Current Can Be Tolerated, ““KK”” Factor Factor Calculation Is Made Instead Of Using Calculation Is Made Instead Of Using The THD(I) FormulaThe THD(I) Formula

Corporate Presentation 12-Apr-2004 EN

Buildinga New Electric World

How do you know if Harmonics are present in your system?

Random logic faults: CNC, PLCs, drives, UPSs, computersRandom Breaker Thermal TripsClocks Running Faster

Other Common symptoms of harmonics include:



Common Symptoms of Harmonics (cont.)

Potential Resonance Condition> Over Voltage

Power Factor Capacitor > Harmonic heating effect> Trips on over-current

Limits on capacity of UPSsGenerator faulting-Unable to do frequency regulation



SYSTEM CAPACITY ISSUE

Displacement Power FactorTrue or Total Power Factor


Power Factor is the ratio of Power Factor is the ratio of Active PowerActive Power to to Total PowerTotal Power::

Power Factor = Active (Real) PowerTotal Power

= kW kVA

= Cosine (θ)= Displacement Power Factor (DPF)

Total Power (kVA)

φActive Power (kW)

ReactivePower

Power Factor is a measure of efficiency (Output/Input)

The Power Triangle:The Power Triangle:

Total Power FactorTPF = (DPF) x (Harm coefficient)

DPF =KW

KVAf= Cos φ

Harm coefficient =1

1 + THD(I)2

TPF = Total or true power factor

DPF = Displacement power factor

Harm coefficient = Harmonic power factor

= Cos δ

Total Power Factor Example

• Variable frequency drive (PWM type)

• DPF = .95

• TDD = 90% – (no DC choke & no input line reactor)

• Harm coefficient =

• TPF = .95 x .7433 = .7061

11 + .92

= .7433


How are Harmonic measured ?How are Harmonic measured ?

North American StandardANSI Standard IEEE 519-1992

IEEE Recommended Practices and Requirements for Harmonic Control in

Electrical Power Systems

ANSI Standard IEEE 519-1992

• Chapter 11– Addresses THD(V) delivered by utility to user– THD(V) must be < 5% [< 69 KV systems]

• Chapter 10– Defines the amount of TDD a user can cause– Based upon Demand Load & System Fault Level– Table 10.3 for systems < 69 kV– Defines limits for voltage notches caused by SCR

rectifiers – Table 10.2

• Defines PCC (point of common coupling)

IEEE 519-1992 Table 10.2Limits on Commutation Notches

(Applies to SCR rectifiers – only)

*Special Applications – Airports, Hospitals** Dedicated System – Dedicated exclusive to converter loads

Table 10.2Low-Voltage System Classification and Distortion Limits

*SpecialApplications

GeneralSystem

**DedicatedSystem

Notch Depth 10% 20% 50%THD (Voltage) 3% 5% 10%Notch Area, μVs 16,400 22,800 36,500

Note: Notch area for other than 480 V systems should be multiplied by V / 480.

IEEE 519 - Harmonic Distortion Limits

• Table 11.1 - Voltage Distortion Limits

100*1

50

2

2

V

VTHD h

h∑==

Bus voltage at PCC Max. individual Voltage

distortion (%) Total Voltage distortion THD (%)

69kV and below 3.0 5.0 69.001 kV through 161kV 1.5 2.5 161.001kV and above 1.0 1.5 The limits listed above should be used as system design values for the “worst case” for normal operation (conditions lasting longer than one hour). For shorter periods, during start-ups or unusual conditions, the limits may be exceeded by 50%.


TTotal otal HHarmonic armonic CCurrent urrent DDistortionistortionIs Same AsIs Same As

TTotal otal DDemand emand DDistortionistortion (TDD)(TDD)

+ += ×

∑I I I

I

I

ITDD

h22

4

1 1

100 100L

%

h2

2= × =I 32

%+

∞

2

IEEE 519-1992 Table 10.3Current Distortion Limits for General

Distribution Systems (<69 kV)

Isc/Iload <11 11<=h<17 17<=h<23 23<=h<35 h>=35 TDD<20 4.0% 2.0% 1.5% 0.6% 0.3% 5.0%

20<50 7.0% 3.5% 2.5% 1.0% 0.5% 8.0%50<100 10.0% 4.5% 4.0% 1.5% 0.7% 12.0%

100<1000 12.0% 5.5% 5.0% 0.2% 1.0% 15.0%>1000 15.0% 7.0% 6.0% 2.5% 1.4% 20.0%

Isc = short circuit current capacity of sourceIload = demand load current (fundamental)

(TDD = Total harmonic current distortion measured against fundamental current at demand load.)

TDD = Total Demand Distortion

•

Utility

Customer 1 Customer 2

PCC 1 PCC 2

Other customers

IEEE 519-1992 Chapter 10 states “…Within anindustrial plant, the PCC is the point between the nonlinear load and other loads.”Most harmonic problems are not at PCC with utility

>Occurs with generators & UPS>Occurs where nonlinear loads are concentrated

>Occurs inside the plant

Need to protect the user by moving the harmonic mitigation requirements towhere harmonic loads are located

Specification Issues• Write Separate harmonic spec from nonlinear

load spec (Section 16)– Write standard nonlinear load specification– It is System Standard & NOT Product Standard

• Universal solution is more Cost Effective– Good for all nonlinear loads– Apply AHF per electrical bus (best economics)

• 5% TDD per load or bus inside the plant ?– IEEE 519-1992 Chapter 10 states “…Within an industrial plant, the

PCC is the point between the nonlinear load and other loads.”

• Write TDD specs not THD(I)

Methods For Harmonics Mitigation

**Individual Device Solution•Embedded Solution

**System Solution

Individual Device Solution

Harmonic Mitigation Methods

• Typically applied per device:-Isolating Harmonic Loads--Line reactors– 5th harmonic filters (Only 5th)– Broadband filters (up to 13th)Embedded Solutions:

– Multi-pulsing (6-Pulse,18-Pulse)– Active front end (AFE) converter– C-Less Technology

• System solution– Active Harmonic Filter– Harmonics Mitigation Transformer (Up to 19th)

Inductors

•Pros:– Inexpensive & reliable– Transient protection for loads– Big TDD reduction (90% to 35% w/3% Z)– Complimentary to active harmonic control

•Cons:– Limited reduction of TDD at equipment

terminals after 3% Z

– Reduction dependent on sourceImpedance

Input Current Distortion as a Function of inductor Size

0%10%20%30%40%50%60%70%80%

0 1 2 3 4 5

Inductor Size (% on Drive Base)

Inpu

t Cur

rent

Dis

torti

on (%

)


Current Distortion THD(I) or TDD as a function of Rsce Current Distortion THD(I) or TDD as a function of Rsce With 6With 6--pulse power converterpulse power converter

Multi-pulse ConvertersHarmonic Orders Present

Hn1 phase 4-pulse

2 phase 4-pulse

3 phase 6-pulse

3 phase 12-pulse

3 phase 18-pulse

3 x x5 x x x7 x x x9 x x11 x x x x13 x x x x15 x x17 x x x x19 x x x x21 x x23 x x x x25 x x x x27 x x29 x x x31 x x x33 x x35 x x x x x37 x x x x x39 x x41 x x x43 x x x45 x x47 x x x x49 x x x x

Harmonics present by rectifier designType of rectifier

Hn = NP +/- 1

Hn = harmonic order present

N,n = an integer

P = number of pulses

Harmonic mitigation methodsVFD mitigation topologies

• 6-Pulse converter

“C-less” or 3% reactance min (if included); small footprint, simplified cabling

Current waveform distortedTDD 30% to 40% with 3% reactor (depending on network impedance)

Externally mounted 3 winding transformer; more wire andcabling; complicated

Current slightly distortedTDD 8% to 15% (depending on network impedance)

• 12-Pulse converter • 18-Pulse converter

Large footprint, more steel& copper (losses)

Current wave form goodTDD 5% to 7% (depending on network impedance)

0

100

A

6 pulse

0

100

A

12 pulse

0.0s 0.02s

0

100

A

18 pulse

+

-

DC Bus Load

Delta

Delta

Wye

AC Line

A

B

C

DC+

DC-

LineReactor

Rectifier Assembly

TransformerTertiary

MultipulseTransformer

A

BC

1

2

3

4

56

7

8

9

DC LinkReactor

M

Multi-Pulse Drives

Description: Drives/UPS with two (12 pulse) or three (18 pulse) input bridges fed by a transformer with two or three phase shifted output windings.

•Pros:– Reduces TDD to 10% (12 pulse) & 5% (18 pulse) at

loads– Reliable

•Cons:– High installation cost with external transformer– Large footprint (even w/autotransformer)– Series solution with reduction in efficiency– One required for each product– Cannot retrofit


Active Front End ConverterProducts with active power converter and input broadband filter to create sinusoidal current & voltage waveforms on AC lines.

AC

Source Filter

Converter Inverter

DC Bus

AC Motor

IGBT IGBT

VFD


AFE Converters>Pros:

Meets 5% TDD limit of IEEE 519

200 KVA rated

PWM VFD

DC Drive

PF caps

100 KVA rated

AFE VFD

Mains

>Cons:Larger and more expensive than 6 pulse drivesApproximately twice the size & priceMains voltage must be free of imbalance and voltage harmonics

– Generates more harmonicsWithout mains filter THD(V) can reach 40%Requires short circuit ratio > 40 at PCCSwitched mode power supplies prohibitedCapacitors prohibited on mainsIGBT & SCR rectifiers prohibited on same mains

– No other nonlinear loads permitted


Harmonic mitigation methods(Applied per VFD)

Solution Advantage Disadvantage Typical % TDD Typical Price Multiplier*

Increase short circuit capacity Reduces THD(V)Increases TDD Not likely to occur**

Dependent upon SCR***

Cost of transformer and installation change out

C-Less Technology

Lower TDDSimplified designLess cost

Compliance is limited Application limitedSize limited 30 - 50% TDD 0.90 - 0.95

Impedance (3% LR or 5% DC choke)

Low cost adderSimple Compliance difficult 30 - 40% TDD 1.05 - 1.15

5th Harmonic filter Reduces 5th & total TDDDoes not meet harmonic levels at

higher orders^ 18 - 22% TDD 1.20 - 1.45

Broadband filter Reduces TDD (thru 13th)Large heat losses Application limited 8 - 15% TDD 1.25 - 1.50

12-pulse rectifiersReduces TDD Reliable

Large footprint/heavyGood for >100 HP 8 - 15 % TDD 1.65 - 1.85

18-pulse rectifiersReduces TDDReliable

Large footprint/heavy Good for >100 HP 5 - 8% TDD 1.65 - 1.85

Active front end converterVery good TDD Regeneration possible

Large footprint/heavyVery high cost per unit High heat losses < 5% TDD 2.0 - 2.5

* Price compared to a standard 6-pulse VFD.

** Utilities and users are not likely to change their distribution systems.*** Increasing short circuit capacity (lower impedance source or larger KVA capacity) raises TDD but lowers THD(V).^ Can be said for all methods listed.


System SolutionApplied to one or many nonlinear loads

When wave shapes with different phase shifts are combined

Application of Harmonic Mitigation Transformers

54

AccuSine® PCS

**Guarantees elimination of harmonic problems – both TDD and THD(V)** 2nd through 50th order

System SolutionActive Harmonic Filter

• Applied to one or many nonlinear loads– VFD, UPS, UV, DC drives, DC power

supplies• Provides DPF correction• More cost effective for multiple loads• Saves space• Lower heat Losses

Active Harmonic Filter:System Solution

AHFLoad

CT

Source

AHF

•Parallel connected

•Is + Ia = Il

•Ia includes 2nd to 50th harmonic current

•Is <5% TDD

L

Is

Ia

I l

~

57

Active Harmonics Filter

Source non linearload

activeconditioner

I.s I.h

I.ac

I. source I. Harmonics

-2-1,5-1

-0,500,51

21,5

=+-2

-1,5-1

-0,50

0,51

1,52

-2-1,5-1

-0,50

0,51

2

1,5

-2-1,5-1

-0,50

0,51

1,52

I. Active Conditioner I. resultant

AHF off AHF onOrder % I fund % I fundFund 100.000% 100.000%3 0.038% 0.478%5 31.660% 0.674%7 11.480% 0.679%9 0.435% 0.297%11 7.068% 0.710%13 4.267% 0.521%15 0.367% 0.052%17 3.438% 0.464%19 2.904% 0.639%21 0.284% 0.263%23 2.042% 0.409%25 2.177% 0.489%27 0.293% 0.170%29 1.238% 0.397%31 1.740% 0.243%33 0.261% 0.325%35 0.800% 0.279%37 1.420% 0.815%39 0.282% 0.240%41 0.588% 0.120%43 1.281% 0.337%45 0.259% 0.347%47 0.427% 0.769%49 1.348% 0.590%% TDD 35.28% 2.67%

AHF HarmonicsPerformance

AHF injection

Source current

At VFD Terminals


AccuSine® PCS Overall Performance

Harmonic compensation2nd through 50th order Includes inter-harmonicsIndependent of source impedance

– Selection and operation same whether on AC line or backup generator or UPS output

Obtain 5% TDD (current distortion)

Reactive current injection ( VAR Correction)Reactive current injection is secondary to harmonic mitigation

Either or both functionsVAR compensation

100 μsecond detect-to-injectDynamic response

½ cycle to full control for step load changes

Dual Mode Operation

Ias = Ih2 + Ir

2

Ias = rms output current of AHF

Ih = rms harmonic current

Ir = rms reactive current

Ias Ih Ir100.0 10.0 99.5100.0 20.0 98.0100.0 30.0 95.4100.0 40.0 91.7100.0 50.0 86.6100.0 60.0 80.0100.0 70.0 71.4100.0 80.0 60.0100.0 90.0 43.6100.0 95.0 31.2

Examples


AccuSine® PCS

AdvantagesHighly effective (2nd to 50th orderscancelled)Scalable

– Parallel units as neededUniversal solution

– Handles many loads– Many types of loads at same

timeHMI & Modbus CommunicationBest cost for multiple loads

– Lowest heat profileSmallest footprint with std VFD/UPS

DisadvantagesHeat from high speed switching of IGBTCost issues possible forsingle load

ConsiderationsLoad must have input impedance (3%)

– Protects load– Limits size of AHF

Need branch circuit protection


AccuSine® PCS Specifications

Universal Application208 – 480 VAC

– No user action required to set50 or 60 HzUse highly customized transformers for higher voltages (to 15 kV)

Fuse protected (200,000 AIC)UL 508 & CSA approvedCE (EMC) - 400VLogic ride through – 1 to 10 minutes

Power Diagram For A Typical AHF

+C

E

C

E

C

E

C

E

C

E

C

E

C

LineInductor

FilterBoard

Pre-charge Contactor

Inductor

Fuse

Fuse

Fuse

ACLines

DC Bus Capacitors

S4

S5

S6

S1

S2

S3

IGBT Module


Product Package

Standard (UL/CSA, ABS)Three sizes-50A,100A,300ANEMA 1, 1A, 12, & 3R Enclosed – NEMA 1

50 amp – 52” x 21” x 19”– Weight – 250Lbs

100 amp – 69” x 21” x 19”– Weight – 350 Lbs

300 amp – 75” x 32” x 20”– Weight – 775 Lbs

Chassis – IP00Wall mount – 50 & 100 ampFree standing – 300 amp with disconnect


Product PackageInternational enclosures

NEMA 12, IP30, IP54– 50 amp – 75” x 31.5” x 23.62”– Weight – 661 Lbs– 100 amp – 75” x 31.5”x 23.62”– Weight – 771 Lbs– 300 amp – 91” x 39.37” x

31.5”– Weight – 1212 Lbs

Free standing with door interlocked disconnectCE Certified, ABS, UL, CUL


Product Re-packaging

Maximum ambient into air inlet – 400CMust meet air flow at inlet of AccuSine

50 amp – 300 CFM100 amp – 500 CFM300 amp - 1250 CFM

Heat released50 amp – 1800 watts100 amp – 3000 watts300 amp – 9000 watts

HMI considerations requiredOn chassisRemote with cable


Product Re-packaging

MCC Packaging50 & 100 amp models onlyRequires one vertical 20” x 20”sectionIncludes circuit breaker in section


Comparison of 18-P VFDTo

AccuSine + 6-P VFD+3%LR


System SolutionAccuSine® PCS Sizing Example

A 125 HP variable torque 6-pulse VFD with 3% LRRequired AHF filtering capability = 47.5 amperes

Two 125 HP VT 6-pulse VFD w/3% LRRequired AHF size = 84.4 amps

Three 125 HP VT 6-pulse VFD w/3% LRRequired AHF size = 113.5 amps

Six 125 HP VT VFD w/3% LRRequired AHF size = 157.6 amps

– (not 6 x 47.5 = 285 amps)


Footprint requiredAccuSine PCS+ Std VFD less than 18-P VFD (w/autotransformer) for all conditions

Heat lossesAccuSine PCS+ Std VFD less than 18-P VFD

– Exception at single units of 50-75 HP, advantage 18-P VFDLess Operating Cost AccuSine PCS+ 6-P VFD

Less site cooling required with AccuSine PCS + Std VFDPrice ( Installed Cost)

When more than one VFD, AccuSine PCS + 6-P VFD always beats 18-P VFDIf only one VFD involved, 300-500 HP sizes favor 18-P VFDSQ D Software Tool

System solutionComparison of 18-P VFD to AccuSine + 6-P VFD+3%LR

AccuSine to18-pulse Comparisons

IR: 10.00% kWH rate: $.10 Days/week: 7Years: 10 Hours/day: 24

System: 1x 125 HP 1x 150 HP 1x 200 HP 1x 300 HP 1x 400 HP 1x 500 HP

18-pulseAccuSine System 18-pulse

AccuSine System 18-pulse




AccuSine System

User Price 35,914.49 31,342.92 38,893.84 43,866.16 50,507.30 47,771.37 62,107.17 71,451.53 70,875.00 89,389.61 77,962.50 99,703.69Sq Ft 9.03 5.02 9.03 5.02 9.03 5.02 18.06 10.81 18.06 10.81 18.06 10.81Annual operating costs 4,228.22 3,960.89 5,084.35 4,342.66 6,534.53 5,102.25 9,286.37 8,428.81 12,116.83 10,178.29 15,331.68 11,968.30

NPV Cash Flow 6,257.33

Advantage: AccuSine System -295.25

Advantage: 18-pulse 11,767.77

Advantage: AccuSine System -4,277.20

Advantage: 18-pulse -6,290.32

Advantage:18-pulse -531.93

Advantage:18-pulse







AccuSine System



Advantage: AccuSine System 9,401.64

Advantage: AccuSine system 33,435.03




Advantage: AccuSine system







AccuSine System








Advantage: AccuSine system


AccuSine® PCSInstallation Considerations

AHFInstallation Considerations

This configuration provides individual AHF operation per side regardless of breaker positions.

Main – Left Main – Right

CBml CBmr

Tie

CTml CTtl CTtr CTmr

AHF-RAHF- L

CBal CBar

Main-tie-main

AHF Installation Considerations

Regardless of Main Power CB and Generator CB positions, AHF limits harmonics for both sources.

AHF

Main Power CB

Generator

Generator CB

Utility

CTm CTg

CBa

~

AccuSine PCS Limitations

• 3-Phase / 3-Wire design only– Does not help neutral harmonics

• “Sine-Wave” Product for 3-Phase / 4-Wire System

AccuSine Selection• Use Spreadsheet—SQ D Software• No Harmonics Analysis required• Information Required for Sizing:

* One Line* All VFDs Details—HP & CT or VT* All Linear Loads Details-HP/KW* Other Non-Linear Loads—UV / OG* If DPF Correction is required.* Both LV & MV Bus

* Add 3% LR for all Non-Linear Loads

Generator & Harmonics Load

Generator Feeding Nonlinear Loads

• Soft Source• High Impedance with limited over load capacities• High Impedance produces excessive THDv• High THDv directly affects Voltage Regulation• Many existing Generators with old Regulator Design can fail• High THDv affects Electronics Loads & can fail


Voltage distortion THD(V) as a function of RSCE Voltage distortion THD(V) as a function of RSCE with 6with 6--pulse power converterpulse power converter

Generator Feeding Nonlinear Loads

*Harmonics Current Generates Excessive Heatingin the Windings*Derating of Generator needed with Nonlinear Loads

Generator Feeding Nonlinear Loads:AccuSine Advantages

*Helps Generator runs “Cooler”*Helps Voltage Regulation*Helps Older Existing Generators in the Field*Helps Retrofits– Space & Generator Rating*Helps Environment

Solution Approach

Solution Cycle

Measure

Simulate

Specify & Propose

Supply & Commission

Analyze & Report


Thank You !Thank You !Questions?Questions?

For More Information, Please Contact:B. Ben BanerjeePower Quality Correction GroupSchneider ElectricSan Francisco Field OfficeDirect: 925-463-7103Cell: 925-858-2182E-mail: [email protected]

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