Presented at the IEEE Nashville Chapter · 2016. 5. 3. · IEEE Nashville Chapter Presented by...

Schneider Electric Engineering Services

Harmonic Reduction Techniquesq

Presented at the

IEEE Nashville Chapter

Presented by

R T j li P EReza Tajali, P.E.Tel: 615-844-8663 Email: [email protected]


All Your Problems Are NailsBecause We Have a Hammer


Harmonics, Key Concepts

I Wh t i th bl ith h i ?I. What is the problem with harmonics?II. How do they come about?III How do they add up?III. How do they add up?IV. The concept of power quality as voltage qualityV. How to reduce them?V. How to reduce them?


II-The Single Phase Power Supply

Rectifier

EMI Filter

Voltage Regulator

Rectifier

Line DC BusFilter g


II. The Three Phase Power Supply

1 0

-0.5

0.0

0.5

1.0

Current

DC BusLine 0 10 20 30 40

-1.0

Time (mS)

0.5

1.0

ent

0 10 20 30 40-1.0

-0.5

0.0

Time (mS)

Curr

1.0

-0.5

0.0

0.5

Current

0 10 20 30 40-1.0

Time (mS)


III. How do Harmonics Add Up?

Fundamental (1st harmonic) 85%Fundamental (1st harmonic) - 85%3rd harmonic - 45%5th harmonic - 27%


III H d H i Add U ?III. How do Harmonics Add Up?Distorted Current Waveform 7th Harmonic Component

Instantaneous Relationship i = i1 + i2 + i3 +………..

RMS Relationship I2 = I12 + I22 + I32 + …………..


C Hi t #1 M f t i Pl tCase History #1 Manufacturing Plant Generator Cross Talk Harmonics

1100 Amps RMS Phase300 Amp 3rd harmonicon neutral

LoadLoad

on neutral

G G2000 KVA480Y277Solid GRND

450 KW480Y277

Solid GRND

450 KW480Y277

Solid GRND


How Bad is the Third Harmonic?

1100 Amp RMS Fund.A

B1100 Amp RMS Fund.

C

N

1100 Amp RMS Fund.

300 Amp RMS 3rd Harmonic

•Third Harmonic = 9% of Fundamental•Total I2 = (1100)2 + (100)2•Total I = (1100) + (100)•I = 1104 Amps

9% Third Harmonic Adds only 0.4% to Total RMS


No Voltage Distortion

IV. Power Quality is Voltage Quality

Distorted Voltage


Impedance

DistortedCurrent

Non-LinearL d

SinusoidalVoltageS

MLoadSource


C Hi t #2Case History #2Hospital’s Emergency Generators

Synch BusSy c us800 KW LoadVTHD = 5%

1000 KW 1000 KW

G G G

1000 KW


Hospital’s GeneratorsGenerator Paralleling Switchgear

May 12th Testingy g

30%

35%

600

700

kW

20%

25%

THD 400

500

10%

15%Vol

tage

200

300

kW

VTHD

0%

5%

5:15 5 :20 5 :25 5 :30 5 :35 5 :40 5 :45 5 :50 5:55 6 :00 6:05 6:10 6:15

0

100

5 :15 5 :20 5 :25 5 :30 5 :35 5 :40 5 :45 5 :50 5:55 6 :00 6:05 6:10 6:15

VTHD kW


V-Methods of Reducing Voltage Distortion

1 Isolate Harmonic Loads1- Isolate Harmonic Loads2. Reduce Generated harmonics

Chokes, inductors, Isolation Transformer12 or 18 Pulse Drives

3- Reduce system impedance (Stiffen the source)4- Remove or reduce PF correction capacitors if4- Remove or reduce PF correction capacitors if

resonance is present5- Use transformers to cancel harmonics

f f6- Install capacitor-based harmonic filters if power factor is low

7- Install an active filter


1 S t L d1. Segregate LoadsIEEE-1100

BAD GOODBAD GOOD

Sensitive LoadsSensitive LoadsOther LoadsOther Loads Other LoadsOther Loads Sensitive LoadsSensitive Loads


2 - Inductors Reduce the Generated Harmonics

1500 kVA Transformer

3% AC Choke

ASD

3% AC Choke

OthOtherLoads


Why Inductance?TYPE 1 Waveform

100 HP PWM ASD N Ch kTYPE 2 Waveform

100 HP PWM ASD 3% Ch k

0

200

400

100 HP PWM ASD - No Choke

Amps

100 HP PWM ASD - 3% Choke

0

200

400

Amps

0.05 0.06 0.07 0.08 0.09 0.10-400

-200

Time (Seconds)

p

0.05 0.06 0.07 0.08 0.09 0.10-400

-200

Time (Seconds)

p

100% 100%

50%

60%

70%

80%

90%

100%

ITHD = 80.6%IRMS = 148.2 AmpsIFund = 115.4 Amps

50%

60%

70%

80%

90%

100%

ITHD = 37.7%IRMS = 117.6 AmpsIFund = 110.1 Amps

0%

10%

20%

30%

40%

50%

H

0%

10%

20%

30%

40%

1 3 5 7 9 11 13 15 17 19 21 23 25Harmonic Number

1 3 5 7 9 11 13 15 17 19 21 23 25Harmonic Number


3 - Reduce System Source Impedance



3% AC Choke

ASD

3% AC Choke

OthOtherLoads


i4 – Remove or Reduce CapacitorsWhen Resonance is Present

1000

130 KVAR1000 KVA

100O

hms No Capacitor

130 KVAR600 KVAR

Ih

1

10

OIh

1

0 5 10 15 20 25 30 35Harmonic

PWM

M

800 HP


5 – Use Transformers to Cancel Harmonics

480V

Delta -Wye Transformers‘Cancel’ 3rd, 9th, 15th Harmonics

ComputerPanelA

B

480VPanel

CN

208Y/120


30KVA 208 - 208Y/120

10 0020.0030.0040.00

20.0040.0060.0080.00

TransformerPrimary Secondary

-40.00-30.00-20.00-10.000.00

10.00

Harmonic Angle Amperes1 -66 20 70

-80.00-60.00-40.00-20.000.00

20.00

Harmonic Angle Amperes1 -64 18 901 -66 20.70

3 -113 0.195 -144 7.667 -61 3.569 24 0.1711 -64 1.6613 24 0 93

1 -64 18.903 -15 14.315 41 7.867 121 3.489 -137 2.3811 -53 1.6413 34 0 7713 24 0.93

15 111 0.1213 34 0.7715 154 0.60

RMS Current 22.45THD 41.92%

RMS Current 25.40THD 89.82%

K-Factor 6.12Real Power 3.332kWApparent Power 8.466kVAPower Factor 0 39

K-Factor 8.35Real Power 2.850kWApparent Power 9.153kVAPower Factor 0 31Power Factor 0.39 Power Factor 0.31Neutral Current 43.56A (171%)


Phase Shifting Drive Currents

AFD

480VPanel

Drive 1Panel

AFD

Drive 2


Phase Shifting Computer Load Currents

ComputerPanelAA

BCN

208Y/120480VPanel

Computer

Panel

ComputerPanelA

BCN

208Y/120


Phase Shifting Drive Currents

AFD

480VPanel

Drive 1Panel

AFD

Drive 2



6. Install Capacitor-based Harmonic Filters

Distorted Voltage


Impedance

DistortedCurrent

Non-LinearL d

SinusoidalVoltageS

MLoadSource


0 30

Harmonic Filter Utilizes Resonance

0.25

0.30

0.15

0.20 Parallel Resonance

0.10

ce, o

hms

0 6 12 18 24 300.00

0.05

4

Series Resonance

Impe

danc

Frequency (H pu)


Filter Application

2000 KVA 600800 Current

Ih

400

-200

0

200

400

-800

-600

-400

VoltagePF

Controller

PWM

M Ih

1500 HPBad Application


Filter Application

2000 KVA

Ih

Linear

MPF

Controller

Linear1000 KW

@ 80% PF

PWM

M Ih

800 HP Good Application


Filter Application

1500 KVA

Ih

PF Controller

SCR based converter

85% DPF

1000 KVAOzone Gen

Ih

85% DPF

Good Application


7 – Install Active Filter

-2

-1,5

-1

-0,5

00,5

11,5

2

21

--0

00,5

11,5

2

-2

-1,5

-1

-0,5

00,5

11,5

Active Filter

MCC BUS-2

-1,5

-1

-0,5

00,5

121,5

-2

-1,5

10,5

5

=+

MCC BUS

M

MM M


The Active Filter

Pre-charge C t tContactor

AC Line

High Frequency

FiltFilter Board


How it Works

Controls

AC Source

Active Filter

Harmonic Source

Presented at the IEEE Nashville Chapter · 2016. 5. 3. · IEEE Nashville Chapter Presented by...

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Transcript of Presented at the IEEE Nashville Chapter · 2016. 5. 3. · IEEE Nashville Chapter Presented by...