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Presented at the IEEE Nashville Chapter · 2016. 5. 3. · IEEE Nashville Chapter Presented by...
Transcript of Presented at the IEEE Nashville Chapter · 2016. 5. 3. · IEEE Nashville Chapter Presented by...
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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]
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All Your Problems Are NailsBecause We Have a Hammer
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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?
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II-The Single Phase Power Supply
Rectifier
EMI Filter
Voltage Regulator
Rectifier
Line DC BusFilter g
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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)
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III. How do Harmonics Add Up?
Fundamental (1st harmonic) 85%Fundamental (1st harmonic) - 85%3rd harmonic - 45%5th harmonic - 27%
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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 + …………..
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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
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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
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No Voltage Distortion
IV. Power Quality is Voltage Quality
Distorted Voltage
No Voltage Distortion
Impedance
DistortedCurrent
Non-LinearL d
SinusoidalVoltageS
MLoadSource
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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
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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
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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
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1 S t L d1. Segregate LoadsIEEE-1100
BAD GOODBAD GOOD
Sensitive LoadsSensitive LoadsOther LoadsOther Loads Other LoadsOther Loads Sensitive LoadsSensitive Loads
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2 - Inductors Reduce the Generated Harmonics
1500 kVA Transformer
3% AC Choke
ASD
3% AC Choke
OthOtherLoads
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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
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3 - Reduce System Source Impedance
2500 kVA Transformer
1500 kVA Transformer
3% AC Choke
ASD
3% AC Choke
OthOtherLoads
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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
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5 – Use Transformers to Cancel Harmonics
480V
Delta -Wye Transformers‘Cancel’ 3rd, 9th, 15th Harmonics
ComputerPanelA
B
480VPanel
CN
208Y/120
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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%)
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Phase Shifting Drive Currents
AFD
480VPanel
Drive 1Panel
AFD
Drive 2
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Phase Shifting Computer Load Currents
ComputerPanelAA
BCN
208Y/120480VPanel
Computer
Panel
ComputerPanelA
BCN
208Y/120
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Phase Shifting Drive Currents
AFD
480VPanel
Drive 1Panel
AFD
Drive 2
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No Voltage Distortion
6. Install Capacitor-based Harmonic Filters
Distorted Voltage
No Voltage Distortion
Impedance
DistortedCurrent
Non-LinearL d
SinusoidalVoltageS
MLoadSource
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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)
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Filter Application
2000 KVA 600800 Current
Ih
400
-200
0
200
400
-800
-600
-400
VoltagePF
Controller
PWM
M Ih
1500 HPBad Application
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Filter Application
2000 KVA
Ih
Linear
MPF
Controller
Linear1000 KW
@ 80% PF
PWM
M Ih
800 HP Good Application
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Filter Application
1500 KVA
Ih
PF Controller
SCR based converter
85% DPF
1000 KVAOzone Gen
Ih
85% DPF
Good Application
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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
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The Active Filter
Pre-charge C t tContactor
AC Line
High Frequency
FiltFilter Board
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How it Works
Controls
AC Source
Active Filter
Harmonic Source