© 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and...

59
© 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. [email protected] Moon Township, PA

Transcript of © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and...

Page 1: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

© 2005 Eaton Corporation. All rights reserved.

Applying Harmonic Solutions to Commercial and

Industrial Power Systems  

David G. Loucks, [email protected]

Moon Township, PA

Page 2: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Overview Introduction Harmonic Sources Harmonic Symptoms/Concerns (Problems) IEEE 519-1992 Standard Harmonic Solutions

Drive and Rectifier Solutions Solutions for Commercial Power Systems

Harmonic Solutions for Correcting Power Factor Avoiding Harmonic Resonance Low Voltage Vs. Medium Voltage Solutions

The Economics of Harmonic Reduction Summary Tables and Cost Comparisons

Page 3: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

“Harmonics are not a problem unless they are a problem!”

Page 4: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonics 100%, 60 Hz

2%, 780 Hz

20%, 180 Hz

12%, 300 Hz

4%, 420 Hz

2%, 660 Hz

%100...

%1

24

23

22

I

IIITHDI

Page 5: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonic Sources

Harmonic Sources Power Electronic

Equipment (drives, rectifiers (UPS), computers, etc.)

Arcing Devices (welders, arc furnaces, fluorescent lights, etc.)

Rotating Machines (generators)

Most Common Variable Frequency

Drives UPS Computer Power Supplies Fluorescent Lighting

Page 6: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Voltage Distortion

When current flows from other than an infinite source, the source voltage drops

The higher the source impedance or the higher the load current, the greater the drop

Page 7: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Non-Linear Load Example: 1 switched mode power supply

Page 8: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Time

0s 0.1s 0.2s 0.3s 0.4s 0.5s 0.6s 0.7s 0.8s 0.9s 1.0sRMS(I(L4)) I(L4)

-40A

0A

40A

Frequency

0Hz 0.2KHz 0.4KHz 0.6KHz 0.8KHz 1.0KHz 1.2KHzI(L4)

0A

2.0A

4.0A

1 Switched Mode Power SupplyCurrent Harmonics

5A rms

30A peak6x

60 Hz3.6A 180 Hz – 3rd

3.1A300 Hz – 5th 2.25A

420 Hz – 7th 1.38A 540 Hz – 9th

0.74A

Isc = 22000IL = 5A

Isc/IL = 4400

Page 9: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

1 Switched Mode Power SupplyCurrent Harmonics

%.

.

.

....

%

11563

144100

63

740038102520130

100

2222

1

98765432

I

IIIIIIIITHD

Frequency

0Hz 0.2KHz 0.4KHz 0.6KHz 0.8KHz 1.0KHz 1.2KHzI(L4)

0A

2.0A

4.0A

60 Hz3.6A 180 Hz – 3rd

3.1A300 Hz – 5th 2.25A

420 Hz – 7th 1.38A 540 Hz – 9th

0.74A

Page 10: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Frequency

0Hz 0.2KHz 0.4KHz 0.6KHz 0.8KHz 1.0KHz 1.2KHzI(L4)

0A

2.0A

4.0A

1 Switched Mode Power SupplyCurrent Harmonics

60 Hz3.79A 180 Hz – 3rd

3.35A300 Hz – 5th 2.67A

420 Hz – 7th 1.88A 540 Hz – 9th

1.22A

%.

.

.

....

.

....

128793

834

793

4915331372211

100793

2210881067203530 2222

This is with 65 kA available

Page 11: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Current Distortion vs Available Fault Current

22 kA 115% 65 kA 128%

Why is the current distortion higher with higher available fault current?

Is that the same situation with voltage distortion?

Page 12: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Let’s increase the source impedance

Remember, our power supply was drawing 5A rms

On a 22 kA source, the ratio of Isc/IL= 4400…

essentially an infinite source

Keeping the same load impedance, let’s drop the source short current down (Isc/IL= 20)

Page 13: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

100 A rms Source

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Voltage Distortion Isc/IL = 4400

%....

%

441381

475100

381

0000900450

100

22

1

98765432

V

VVVVVVVVTHD

Frequency

100Hz 150Hz 200Hz 250Hz 300Hz 350Hz 400Hz 450Hz52HzV(L4:2)

0V

10V

20V

22 kA source1st = 381 V3rd = 5.4 V5th = 0.9 V

Page 15: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Voltage Distortion Isc/IL = 20

%......

%

43377

7812100

377

710140870190

100

2222

1

98765432

V

VVVVVVVVTHD

Isc/IL = 201st = 377 V3rd = 9.1 V5th = 7.8 V7th = 4.1 V9th = 1.7 V

Frequency

0Hz 100Hz 200Hz 300Hz 400Hz 500Hz 600Hz 700Hz 791HzV(L5:2)

0V

5V

10V

15V

Page 16: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonic Distortion Standards

Maximum Voltage Distortion in % at PCC*

Below 69kV 69-138kV >138kV

Maximum for Individual Harmonic 3.0 1.5 1.0

Total Harmonic Distortion (THD) 5.0 2.5 1.5

Harmonic Voltage Distortion LimitsIEEE Standard 519 – 1992Harmonic Voltage Distortion LimitsIEEE Standard 519 – 1992

* % of Nominal Fundamental Frequency Voltage* % of Nominal Fundamental Frequency Voltage

Page 17: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonic Distortion Standards

Harmonic Order (Odd Harmonics)

Isc/IL <11 11<h<17 17<h<23 23<h<35 35<h %TDD

Maximum Harmonic Current DistortionIEEE Standard 519 – 1992Maximum Harmonic Current DistortionIEEE Standard 519 – 1992

In Percent of FundamentalIn Percent of Fundamental

<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 2.0 1.0 15.0

>1000 15.0 7.0 6.0 2.5 1.4 20.0

<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 2.0 1.0 15.0

>1000 15.0 7.0 6.0 2.5 1.4 20.0

Page 18: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonic Limits•PCC (Point of Common Coupling) is defined as the point where another customer can be served

From IEEE519A Draft

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Harmonic Limits

From IEEE519A Draft

Update for IEEE 519

The Point of Common Coupling (PCC) with the consumer/utility interface is the closest point on the utility side of the customer's service where another utility customer is or could be supplied. The ownership of any apparatus such as a transformer that the utility might provide in the customers system is immaterial to the definition of the PCC.

Note: This definition has been approved by the 519 Working Group.

http://home.nas.net/~ludbrook/519error.html

Page 20: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonic Symptoms/Concerns Equipment Failure and Misoperation

Notching Overheating/Failure Nuisance Operation Communication / control interference

Economic Considerations Oversizing Losses/Inefficiencies/PF Penalties

Application of Power Factor Correction Capacitors Other Issues

Metering – do you really have a problem? Marketing hype – buy my product! Specmanship - Misinterpretation of the IEEE-519 Standard

Page 21: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

IEEE 519-1992 Standard

MAXIMUM VOLTAGE DISTORTION IN % AT PCC

< 69 kV 69 kV – 161 kV 161 kV

Maximum for Individual Harmonic 3.0 1.5 1.0

Total Harmonic Distortion (THD) % 5.0 2.5 1.5

MAXIMUM HARMONIC CURRENT DISTORTION IN PERCENT OF IL

Individual Harmonic Order (Odd Harmonics)

I SC /IL 11 11h17 17h23 23h35 35 h % 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 2.0 1.0 15.0

1000 15.0 7.0 6.0 2.5 1.4 20.0

Even harmonics are limited to 25% of the odd harmonic limits above.

Current distortions that result in a dc offset, e.g., half-wave converters, are not allowed.

* All power generation equipment is limited to these values of current distortion, regardless of actual ISC / IL.

Where, ISC = Maximum Short Circuit at PCC. IL = Maximum Load Current (Fundamental Frequency) at PCC.

>> than 519 recommendations especially in specs (drives for example)

Voltage or current harmonics ??

PCC?? 102% Current

Page 22: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Reduce Harmonics – Save Money???

Aside from the “power quality” issues (misoperation, damage, etc), harmonics also “cost” you in other ways….

Cost of oversized neutrals (2x), transformers (1.25-2x), generators (1.4-2x), UPS (1.5-2x), k-factor transformers, etc.

kW losses in cables, transformers and other power system components (1-8% losses).

VTHD = 2.3% VTHD = 5.8%

Utility Source Generator Source

Page 23: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Symmetrical Components

Harmonic Sequence Harmonic Sequence1 + 10 +2 - 11 -3 0 12 04 + 13 +5 - 14 -6 0 15 07 + 16 +8 - 17 -9 0 18 0

Page 24: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Reduce Harmonics – Save Money???

• Motor damage, losses (heating) from “negative sequence currents”.

• High harmonics = low total power factor (utility penalties).

60 Hz Rotation

5th Harmonic Rotation

“Negative Sequence Current” • Tries to Rotate Motor in

Opposite Direction

• Causes Motor Losses, Heating and Vibrations

Page 25: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Drive and Rectifier Solutions Line Reactors

• K-Rated/Drive Isolation Transformers

• DC Choke

• 12-Pulse Converter

• Harmonic Mitigating Transformers/Phase Shifting

• Tuned Filters

• Broadband Filters

• 18-Pulse Converter

• Active Filters

Page 26: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Solutions for Commercial Power Systems

• Neutral Blocking Filter

• Harmonic Mitigating Transformers/Phase Shifting Oversized Neutrals

• K-Rated/Drive Isolation Transformers

• Tuned Filters

• Broadband Filters

• Active Filters

• Low Distortion Loads (Lighting Ballasts, Drives, etc.)

Page 27: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

MV Power Factor (optional harmonic filter)

MVSwitchgear

Incoming Utility Service

LV SecondaryUnit Substation

Transformerw/Neutral Blocker

LV SwitchboardWith Harmonic

Loads

MCC

(AFD) AdjustableFrequency Drive(12/18/24 pulse)

PanelboardFeeding

Computers(3rd harmonics)

PFC

PFC

Active

HMT HMT

AFD

M M M

PFC

Free StandingPF Correction

and/or Harmonic Filter

K

AFD AFD

HMT

PanelboardFeeding 120/208V

Harmonic Loads

- Power Factor Correction

- Tuned Filters

PFC

- Active Filters

- Harmonic Mitigating Transformer

- Blocking Filter for 3rd Harmonic

- Multi-pulse Drives (12/18/24)

Active

HMT

- Blocking Filter for Drives

- K Factor TransformerK

LEGEND

Electronic Ballasts

Active

Control/Sensing for Active or Switched Filter

Bus Voltage without Correction

Bus Voltage with Correction

Page 28: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Expected Harmonics

H = NP+/-1

i.e. 6 Pulse Drive - 5, 7, 11, 13, 17, 19,…

Source Typical Harmonics*6 Pulse Drive/Rectifier 5, 7, 11, 13, 17, 19…

12 Pulse Drive /Rectifier 11, 13, 23, 25…

18 Pulse Drive 17, 19, 35, 37…

Switch-Mode Power Supply 3, 5, 7, 9, 11, 13…

Fluorescent Lights 3, 5, 7, 9, 11, 13…

Arcing Devices 2, 3, 4, 5, 7...

Transformer Energization 2, 3, 4

* Generally, magnitude decreases as harmonic order increases

Page 29: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Filter

Harmonic Solutions

480 V

Xs

M

XT

+ -M

Blocking Filter

G

UPSw/Filter

Welder

Low Distortion Electronic Ballast

Oversized Generator

K-Rated

Act

ive

Filt

er

12 Pulse

M

Page 30: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Effect of Drive Line Reactors (IEEE519A)

Page 31: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Phase Shifting – 12 Pulse

From IEEE519A Draft

Page 32: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

CP9000 - 18 Pulse++

Page 33: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Passive Filters (Parallel / Tuned)

3-Winding TX

VFD VFD

ID Fan 1M

ID Fan 2M

13.8 KV

11th 13th

230 kV

Generator

GSU

Station TX

Steel Mill Sub

Arc Furnace

Page 34: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Passive Filters (Series / Broadband)

From IEEE519A Draft

6-Pulse Drive18-Pulse Equivalent

Page 35: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Active Filters

From IEEE519A Draft

Page 36: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonic Solutions for PF

Application of Harmonic Solutions for PF Correction

• Reduce Utility Penalties – Most Common Reason Today

• Resonance Issues

• Reduce Harmonic = Reduce Vars

• LV/MV?

Page 37: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonic Resonance

The “Self Correcting” Problem

- Blow Fuses

- Fail Capacitors

- Damage Transformer

CAP

SCR

kvar

kVAh

Page 38: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonic Resonance - Solutions• Apply another method of kvar compensation (harmonic

filter, active filter, synchronous condenser, etc)

Change the size of the capacitor bank to over-compensate or under-compensate for the required kvar and live with the ramifications.

Page 39: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonic Correction Selectionfor Drives in MCC’s

Drive Quantity

5 10 15 20

10 Hp

50 Hp

125 Hpand up

Parallel / Passive Filter (10-20% Distortion)

SeriesPassive Filter (8-12% Distortion*)

Active Correction (5-20% Distortion)

18 Pulse Drive (5% Distortion*) 30 Hp

* per Drive

Recommendation based on price and MCC integration

Page 40: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Fundamental Neutral Summation

Page 41: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Harmonic Summation in Neutral

Page 42: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Neutral Heating – Oversize Equipment

C

B

A

N0A at 60 Hz

10A at 60 Hz

10A at 60 Hz

10A at 60 Hz

30A at 180 Hz

10A at 180 Hz

10A at 180 Hz

10A at 180 Hz

Page 43: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Neutral Blocking Filter - Blockade

TRANSFORMER ENCLOSURE

PHASE C

PHASE A

PHASE B

SAFETYGROUND

60Hz ANDNON-TRIPLENHARMONICCURRENTS

TO BUILDING STEEL

COMPUTER COMPUTER COMPUTER

NeutralBlocking

Filter

NO 3rd HARMONIC CURRENTSCIRCULATE IN DELTA WINDING

60Hz CURRENT & NON -TRIPLEN HARMONIC CURRENT

60Hz IMBALANCE CURRENT ONLY

Page 44: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Individual Phase Currents

Page 45: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Neutral Harmonic Currents

Page 46: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Solution Summary Tables

Type 2 – Comparison of Solution Options (and Effectiveness) by CORRECTIVE EQUIPMENT

• Shunt/Parallel Filters• Series Filters/Reactors• Transformer Solutions• Other

Table 3 – Comparison of Solution Options by LOAD TYPE• Drives, Rectifiers, 3-Phase UPS• Computers• Fluorescent Lighting• Welding/Arcing Loads• System Solutions

Page 47: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Cost of Harmonic Correction

Description Typical $/kVA*K-Factor 20Reactor 3-4

Capacitors (LV) 12Switched Capacitors (LV) 25

Single-Tuned Fixed Filter (LV) 35Single-Tuned Switched Filter (LV) 40-50

Single-Tuned Fixed Filter (MV) 12Single-Tuned Switched Filter (MV) 15

Blocking Filter (3rd's) 100Blocking Filter (Drives) 100Active Harmonic Filter 150

Phase-Shifting Transformers 50

Note that prices are generalized for comparison only but not absolute.

Some equipment must be fully rated for loads - others can be partially rated

Capacitors are shown for reference only.

Page 48: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Solutions: AF DrivesPros Cons

Line Reactors

Inexpensive For 6-pulse standard

drive/rectifier, can reduce harmonic current distortion from 80% down to about 35-40%

May require additional compensation

K-rated/Drive Isolation

transformer

Offers series reactance (similar to line reactors) and provides isolation for some transients

No advantage over reactors for reducing harmonics unless in pairs for shifting phases

DC Choke

Slightly better than AC line reactors for 5th and 7th harmonics

Not always an option for drives

Less protection for input semiconductors

12-Pulse Convertor 85% reduction versus

standard 6-pulse drives

Cost difference approaches 18-pulse drive and blocking filters, which guarantee IEE 519 compliance

Drives and Rectifiers –

Includes 3-Phase UPS

Loads

Harmonic Mitigating

Transformers/Phase Shifting

Substantial (50%-80%) reduction in harmonics when used in tandem

Harmonic cancellation highly dependent on load balance

Must have even multiples of matched loads

Page 49: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Solutions: AF Drives (continued)Pros Cons

Tuned Filters

Bus connected – accommodates load diversity

Provides PF correction

Requires allocation anaylysy

Sized only to the requirements of that system

Broadband Filters Makes 6-pulse into the

equivalent of 18-pulse

Higher cost Requires one filter per

drive

18 Pulse Converter

Excellent harmonic control for drives above 100HP

IEEE 519 compliant

High Cost

Drives and Rectifiers –

Includes 3-Phase UPS

Loads (continued)

Active Filters

Handles load/harmonic diversity

Complete solution up to 50th harmonic

High cost

Page 50: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Solutions: 1 Power SuppliesPros Cons

Neutral Blocking Filter

Eliminates the 3rd harmonic from load

Relieves system capacity Possible energy savings

High Cost May increase voltage

distortion

Harmonic Mitigating

Transformers

3rd harmonic recalculated back to the load

When used as phase-shifted transformers, reduces other harmonics

Reduces voltage “flat-topping”

Requires fully rated circuits and over sized neutrals to the loads

Oversized Neutral/Derated

Transformer

Tolerate harmonics rather than correct

Typically leased expensive

Upstream and downstream equipment fully rated for harmonics

Computers/ Switch-mode

Power Supplies

K-Rated Transformer

Tolerate harmonics rather than correct

Does not reduce system harmonics

Page 51: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Solutions: Fluorescent LightingPros Cons

Harmonic Mitigating

Transformers

3rd harmonic recalculated back to the load

When used as phase-shifted transformers, reduces other harmonics

Reduces voltage “flat-topping”

Requires fully rated circuits and over sized neutrals to the loads

K-Rated Transformer

Tolerate harmonics rather than correct

Does not reduce system harmonics

Fluorescent Lighting

Low Distortion Ballasts

Reduce harmonics at the source

Additional cost and typically more expensive than “system” solutions

Page 52: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Solutions: Welding, Etc.Pros Cons

Active Filters

Fast response and broad-band harmonic corrention

Reduces voltage flicker

High cost Welding/

Arcing Loads Tuned Filters

SCR controlled tuned filters simulates an active filter response

SCR controlled units are high cost but fixed filters are reasonable

Tuned Filters

Provides PF correction Lower cost compared to

other systems

System analysis required to verify application

Harmonic Mitigating

Transformers

Excellent choice for new design or upgrade

No PF correction benefit

System Solutions

Active Filters Ideal solution and handles

system diversity Highest cost

Page 53: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Review of Solutions

SOLUTION ADVANTAGES DISADVANTAGES Shunt/Parallel Filter Solution

Passive Harmonic Filters

Typically sized to reduce the most prevalent harmonics to an acceptable level

Provides PF correction Avoids resonance by

selecting “tuned” frequency

Requires system knowledge and analysis

Active Harmonic Filter

Excellent cancellation for 2nd through 50th harmonic currents

Cannot be overloaded Handle diversity of loads

Highest cost

Page 54: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Review of Solutions - 2SOLUTION ADVANTAGES DISADVANTAGES

Series Filters/Reactors

Active Harmonic Filter

Excellent power conditioning for removing source voltage harmonics

Highest cost

Neutral Blocking Filters Eliminated 3rd harmonic

current from load

High cost May increase voltage

distortion loads

Broadband Blocking Filters Makes 6-pulse into 18-

pulse equivalent

High cost Requires one filter per

drive

AC Line Reactors

Inexpensive For 6-pulse standard

drive/rectifier can reduce harmonic distortion from 80% to 35% to 40%

May require additional compensation

DC Reactors for Drives

Better than AC line reactors for 5th and 7th harmonics

Not always an option for drives

Less protection for input semiconductors

Page 55: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

SOLUTION ADVANTAGES DISADVANTAGES Transformer Solutions

Isolation Transformers Offers series reactance and

provides electrical isolation

No advantage over reactors for reducing harmonics unless used in pairs for phase shifting

Transformer Derating Lowest cost solution Does not remove the

harmonics

Harmonic Mitigating Transformers/Phase Shifting

Substantial (50% to 80%) reduction in harmonics when used in tandem

Harmonic cancellation highly dependent on load balance

Must have even multiples of unmatched loads

Neutral Cancellation Transformer – Zero sequence

Trap

3rd harmonic recalculated back to the load

Can reduce the 5th and 7th harmonics when used as phase shifting pairs

Reduces voltage “flat-topping”

Requires fully rated circuits downstream to the loads

18 Pulse Drive Systems

Excellent harmonic control for drives above 100HP

IEEE 519 compliant

Higher Cost

K-Factor Transformers Tolerate harmonics rather

than correct

Does not reduce system harmonics

Page 56: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

SOLUTION ADVANTAGES DISADVANTAGES Other

Oversized Neutrals

Live with high 3rd harmonics

Downstream panels and shared neutrals must be oversized

Transformer windings and neutral must be sized for high harmonics

Review of Solutions - 4

Page 57: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Wrap-upPower quality problems are costly ($$$)

Energy management considerations should include power factor analysis

Power factor correction capacitors are typically cost effective solutions to energy management

Harmonics must be considered when applying capacitors

Harmonics problems are increasing with the addition of power electronic loads on the power system

Model the power system based on typical data or measurements

Verify computer model with measurements

Page 58: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Let’s Be Careful Out There!!!

Page 59: © 2005 Eaton Corporation. All rights reserved. Applying Harmonic Solutions to Commercial and Industrial Power Systems David G. Loucks, P.E. DaveGLoucks@eaton.com.

Thank You!

Questions?