Harmonic Solutions for VFD’s
PQ01
Review of Power Control Harmonics, Power
Factor, Distortion & Displacement
PQ02 – Power Quality and Monitoring..
PQ03 – Using Test Eqipment to Detect and
Measure PQ Issues
PQ04 – Understanding Power Monitoring
PD02 – Power Quality and Monitoring
MC04 – Installation Considerations for VFD’s
Related Content at the Expo
What Are Harmonics?
3 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
What Are Harmonics?
4 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Ideal
Often seen
What Are Harmonics?
5 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
What Are Harmonics? What Are
Waveforms?
6 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Rfund.V =...
0
0
40.00m
40.00m
10.00m
10.00m
20.00m
20.00m
30.00m
30.00m
-150.0 -150.0
150.0
0 0
-100.0 -100.0
-50.0 -50.0
50.0 50.0
100.0 100.0
• A sinusoidal waveform has no harmonics
What Are Harmonics and Waveforms?
Rtotal.V =...
0
0
40.00m
40.00m
10.00m
10.00m
20.00m
20.00m
30.00m
30.00m
-150.0 -150.0
150.0
0 0
-100.0 -100.0
-50.0 -50.0
50.0 50.0
100.0 100.0
7 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
• This non-sinusoidal waveform contains harmonics
Let’s Create a Distorted Waveform
Fundamental (1st harmonic) Only
8 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
• fundamental at 60Hz
Fundamental and 5th Harmonic
9 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
• Some 5th harmonic , 153deg
1st, 5th and 7th Harmonics
10 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
•A little of 7th harmonic , 282deg
1st, 5th, 7th and 11th Harmonics
11 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
•A bit of 11th harmonic , 0deg
1st and Sum of the 5th, 7th and
11th
12 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
• Sum the 5th, 7th and 11th harmonic currents
Fundamental, Harmonics, Total
13 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
• Sum the harmonics with the fundamental
FFT and How Are Harmonics
Measured?
14
Power Source
AC Drive
Motor M
Harmonic
Power Meter
Performing FFT
A1 Waveform178.67 Arms, 34.40 %THD
0
20
40
60
80
100
1 5 10 15 20 25 30 35 40 45 5010/28/2010 - 1:46:18.297 PM
FFT, RSS, THD
15 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Harmonic
Number
Frequency
Hz
Amplitude
RMS
Amplitude
RMS^2
Phase
Angle
0 DC 0.00 0.00 0
1 60 70.71 5000.00 357
3 180 0.00 0.00 0
5 300 27.97 782.50 153
7 420 10.85 117.67 282
9 540 0.00 0.00 0
11 660 5.54 30.74 0
13 780 2.79 7.79 81
15 900 0.00 0.00 0
17 1020 2.54 6.44 189
19 1140 1.45 2.09 246
21 1260 0.00 0.00 0
23 1380 1.37 1.88 10
25 1500 0.91 0.84 58
27 1620 0.00 0.00 0
29 1740 0.78 0.61 185
Sum of 3rd to 29th 950.56
Square Root of Sum 30.83 Iharm
Sum of 1st to 29th 5950.56
Square Root of Sum 77.14 Itotal
Iharm = 30.83A
Ifund = 70.71A
Itotal = 77.14A
ITHD = 43.6%
= Iharm / Ifund
What Is I(THD)?
ITHD = Iharm / Ifund
So, Iharm = ITHD * Ifund
16
•ITHD is a ratio between two numbers, it does not stand alone!
We can decrease ITHD
by either decreasing Iharm or increasing Ifund
Frequency, Amplitude, Phase Angle
17 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
•Harmonics are simply integer multiples of the fundamental frequency
– for example, if 60Hz is the fundamental (sometimes referred to as the 1st harmonic), then the 2nd harmonic is 120Hz, the 3rd harmonic is 180Hz, etc.
•Any non-sinusoidal waveform can be created by the addition of harmonics at various amplitudes and phase angles
Electrical Loads and Current Harmonics
18 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Power Source Load Type ?
Line Current Harmonics?
What are Loads That Do Not Have
Current Harmonics?
19 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
• A sinusoidal waveform has no harmonics
• This is an example of a linear load
Voltage Current
What are Loads That Do Not Have
Current Harmonics?
20 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
• A sinusoidal waveform has no harmonics
• This is an example of a linear load
Voltage
Current
Examples of Linear Loads
Induction motors
Incandescent lights
Resistance heaters
Power Factor Correction Caps
Electromagnetic devices
Transformers
non-linear
• During energization
• Over-voltage
21
What are Loads That Have Current
Harmonics?
Rfund.V =...
Rtotal.V =...
0
0
40.00m
40.00m
10.00m
10.00m
20.00m
20.00m
30.00m
30.00m
-150.0 -150.0
150.0
0 0
-100.0 -100.0
-50.0 -50.0
50.0 50.0
100.0 100.0
22
• This is an example of a non - linear load
• A non-sinusoidal waveform contains harmonics
Examples of Non-Linear Loads
Single Phase
Fluorescent lights (ballast)
Incandescent lights with light dimmers
Anything with an ac-dc power supply
Computers (ac-dc PS)
Monitors (ac-dc PS)
TVs (ac-dc PS)
LED lighting
Three Phase
Welders
Arc furnaces
UPS
DC power supplies
DC Drives
Phase control
PWM
AC Drives
6-Step
PWM
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 23
A Typical AC Drive
24
Power Source AC Drive Motor
Line Current Harmonics
M
How Do Drives Create Harmonics?
What Does it Do?
Converter
AC to DC
Inverter
DC to AC
DC
Bus
Filter
AC Drive
AC
Moto
r Outp
utA
C L
ine I
nput
25 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Input Output
480Vac
60Hz
0-460Vac
0-60Hz
650Vdc
Bus = Fixed Vdc
Let’s Look at Some Voltages and
Current
26 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
AC
Power
Line
LoadVab
Vac
Ia
Vbus
First Current Pulse
27 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
AC
Power
Line
Load
Into A
Out of B
1
Second Current Pulse
28 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
AC
Power
Line
Load
Into A
Out of C
2
Typical Current Waveform for 6
Diode (Pulse)
Rtotal.V =...
0
0
40.00m
40.00m
10.00m
10.00m
20.00m
20.00m
30.00m
30.00m
-150.0 -150.0
150.0
0 0
-100.0 -100.0
-50.0 -50.0
50.0 50.0
100.0 100.0
29 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Spectrum – 3ph Diode Bridge
0
10
20
30
40
50
60
70
80
90
100
1 3 5 7 9 11 13 15 17 19 21 23 25
30 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Harmonic Number
% A
mp
litude
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 31
0
10
20
30
40
50
60
70
80
90
100
1 3 5 7 9 11 13 15 17 19 21 23 25
Why do the line currents
contain 5th and 7th
harmonics?
Harmonic Number
Why 5th and 7th?
Harmonics
32 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
2
4
6
8
10
12
14
16
18
20 NOTE: No even harmonics because each half cycle is identical
Rfund.V =...
Rtotal.V =...
0
0
40.00m
40.00m
10.00m
10.00m
20.00m
20.00m
30.00m
30.00m
-150.0 -150.0
150.0
0 0
-100.0 -100.0
-50.0 -50.0
50.0 50.0
100.0 100.0
1
3
5
7
9
11
13
15
17
19
Harmonics
1
3
5
7
9
11
13
15
17
19
33 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
NOTE: No triplens (multiples of 3)
2
4
6
8
10
12
14
16
18
20
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 34
SO WHAT……what do I care
if adjustable speed drives
draw current harmonics
on a power distribution
system?
Issues with Excessive Harmonic Current
35 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Current Harmonics
create
Voltage Distortion
HARMONIC SOURCE
PLC
EQUIPMENT
TELEPHONE
EQUIPMENT
DATA
PROCESSING
CENTER
PCC
IH
Summary of Excessive Harmonic Current Concerns
• Increased Utility current requirement – Inability to expand or utilize
equipment
– Larger wire size needed = increased installation costs
• Component overheating – Distribution transformers,
generators & wires
• Reduced Utility power factor – Increase in utility costs
• Equipment malfunction – Due to voltage distortion with
multiple or loss of zero crossing
– Due to voltage distortion such as flat topping
• Excitation of Power System Resonance's creating over-voltage’s – If PFCC in system
HARMONIC SOURCE
PLC
EQUIPMENT
TELEPHONE
EQUIPMENT
DATA
PROCESSING
CENTER
PCC
IH
PFC PFC
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 36
When Should You Be Concerned
About Harmonics?
If service Transformer is Loaded near rating 60%
20 % of total Load is Non-Linear electronic load
When PF correction capacitors Used or Planned
When Voltage Distortion exceeds 8%
37 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Example of High Ithd with Low Vthd - 1500kVA, 75hp
38 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Ithd = 37% Vthd = 0.9%
Example of High Ithd with High Vthd - 75kVA, 75hp
39 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Ithd = 29% Vthd = 9.3%
Excessive Harmonic Current
Causing Voltage Flat-Topping
40 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Excessive Harmonic Current
Causing Voltages with High Peaks
Event #397 at 12/23/2009 22:19:59.800
Timed
Ev ent Details/Waveforms
22:19:59.86
12/23/2009
Wednesday
22:19:59.87 22:19:59.88 22:19:59.89
-750
-500
-250
0
250
500
750
Vo
lts
D V A-B V B-C V C-A V
41 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
477VAC RMS
720 volts peak
IEEE Std 519-2014
42 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
* Provides harmonic current limits for a facility * Provides harmonic voltage limits for the utility connected to facility
What Are the IEEE 519-2014
Standards?
43 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Application Maximum THD (%)
Special Applications - hospitals and airports 3.0%
General System 5.0%
Dedicated System - exclusively converter load 10.0%
Harmonic Voltage LimitsLow-Voltage Systems
Table 10.2
Application Max Notch Depth
Special Applications - hospitals and airports 10%
General System 20%
Dedicated System - exclusively converter load 50%
Harmonic Voltage Limits
Low-Voltage Systems
Rule of Thumb –
Keep notch depth less than 10% if any other equipment will
be connected to that same point of common coupling.
What Are the IEEE 519-2014
Standards?
44 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Table 10.2
Application Max Notch Depth
Special Applications - hospitals and airports 10%
General System 20%
Dedicated System - exclusively converter load 50%
Harmonic Voltage Limits
Low-Voltage Systems
What Are the IEEE 519-2014
Standards?
45 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Table 10.3
Current distortion Limits for General Distribution Systems (120V through 69,000V)
Isc/Iload <11 11<=h<17 17<=h<23 23<=h<35 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
Isc=maximum short circuit current at PCC
Iload=maximum demand load current (fundamental frequency component) at PCC
Maximum Harmonic Current Distortion in Percent of Iload
Table 10.3
Current harmonics create voltage harmonics so there are current harmonic limits
What Is Ithd vs Itdd?
Ithd = Iharm / Ifund at any speed or load level
Itdd (IEEE519) = Iharm / Ifund at max load
Itdd (xfmr) = Iharm / Ifund at rated transformer current
46 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
6-Pulse Buffered Drive Currents
0
10
20
30
40
50
60
70
80
90
100
0 20 40 60 80 100 % Load
TH
D, F
un
d c
urr
ent, a
nd
Ha
rmo
nic
cu
rre
nt %
Iharm
Ifund
ITHD
How Does Motor Load Affect ITHD?
47 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Ifund decreases as load decreases
Iharm decreases as load decreases
(drive is at full speed)
NOTES:
ITHD = Iharm / Ifund
ITHD increases as load decreases
ITDD
Vthd vs Load
48 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
0
5
10
15
20
25
30
35
40
45
50
0 10 20 30 40 50 60 70 80 90 100
% Load
Ithd, %
Iharm, A
Vthd, %
ITDD
100hp drive on 250kVA xfmr, 6%
Max
Vthd
Why Itdd on Table 10.3?
Itdd is called for because that is a worst case
condition.
Please note:
This is not where Ithd is maximum
But, it is where Vthd is maximum because Iharm is
maximum
When Vthd is a maximum, then greatest likelihood of
problems exist
49 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
The Goal of IEEE 519
50 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Thou Shalt Not
Mess Up
Thy
Neighbor’s
Line Voltage
Thou
Shalt Not
Mess Up
Thy
Neighbor’s
Line Voltage
Who Is Your Neighbor?
51 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
transformertransformer
PCC1
2500kVA
5.75%Z
480Vsec
utility
2500kVA
5.75%Z
480Vsec
utility
Other
Customer
Customer
A
Other
Customer
Customer
B
Other
Customer
Customer
C
Iharm A
Iharm B
Iharm C
Ifund A
Ifund B
Ifund C
Iharm
Ifund
I(TDD) is measured at each metering point
Goal is to
keep the V(THD) at
PCC1 <= 5%,
Example
52 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
transformertransformer
PCC1
2500kVA
5.75%Z
480Vsec
utility
2500kVA
5.75%Z
480Vsec
utility
Other
Customer
Customer
A
Other
Customer
Customer
B
Other
Customer
Customer
C
113Arms
101Arms
72Arms
981Arms
926Arms
1053Arms
241Arms
2960Arms
I(TDD) limits are met at each metering point
at PCC1:
V(THD) = 3.6%
300hp 6-p drives
600hp linear load
80hp unbuf drives
700kW linear load
1000hp 12-p drives
What About Within Customer A or B
or C?
113Arms
981Arms
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 53
Meets IEEE 519 at PCC1 and within plant
PCC1
Isc/Iload = 53.3
V(THD) = 2.0%
I(TDD) = 11.5%
V(THD) <= 10%
Customer A
V(THD) <= 8%
300hp 6-P drives
600hp linear loads
V(THD) <= 8%
What About Back-up Generator?
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 54
Meets IEEE 519 within the plant if the generator is sized properly
PCC1
Isc/Iload = 53.3
V(THD) = 2.0%
I(TDD) = 11.5%
V(THD) <= 10%
Customer A
V(THD) <=8%
300hp 6-P drives
600hp linear loads
G V(THD) <8%
Information Needed for Generator
Applications
Generator Issue Information Required
kW Rating Prime Mover / Engine Specifications Generator Reactive Capability Curve
kVAR Lagging Generator Reactive Capability Curve
kVAR Leading Generator Reactive Capability Curve
Voltage Distortion Generator Impedance, Xd”
Voltage Notching Generator Impedance, Xd”
Harmonic Current Regulator Control
Drive Precharge Regulator Control
Table 3 – Generator Issues and Information Required to Understand and Resolve those Issues.
55 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
General Guidelines For 6 pulse drives Generator sized 250% of Drive HP
For 18 pulse drives Generator sized 125% of Drive HP
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 56
HARMONIC
Current
Ireact
Ireal
Ifund
Itotal
Iharm
(in phase with
line-to-neutral
voltage, VLN)
REACTIVE
Current
Q
P
S1
S
D
x-axis
y-axis
z-axis
REAL
Current
222 DQPS
What is the Power Factor
of a
Non-Linear load?
Linear Load Power Factor Non-Linear Load Power Factor
No Current Distortion Includes the Effect of Current Distortion
PF = Watts/VA
or phase angle between
voltage and current
What About the Power Factor?
Power Factor
Displacement power factor - PF(disp) PF(disp) = Ireal / Ifund = a number between .01 and 1.0
involves only the fundamental quantities
includes the real and reactive currents
Distortion power factor - PF(dist) PF(dist) = Ifund / Itotal = a number between .01 and 1.0
includes the fundamental and harmonic (distorted) currents
Itotal = fundamental and harmonic currents
57 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Total PF = PF(disp) * PF(dist)
Current Amplitudes
• Itotal = 105.6Arms • Iharm = 33.1Arms
• I5 = 29.3Arms
• I7 = 10.9Arms
• I11 = 7.9Arms
• I13 = 4.5Arms
• ……. • Ifund = 100.3Arms
• Ireal = 98.6Arms
• Ireact = 18.0Arms
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 58
Current Amplitudes
• Itotal = 105.6 Arms
• Iharm = 33.1 Arms
• Ifund = 100.3 Arms
• Ireal = 98.6 Arms
• Ireact = 18.0 Arms
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 59
Current Relationships
Itotal = 105.6Arms
• Iharm = 33.1Arms
• Ifund = 100.3Arms
Ireal = 98.6Arms
Ireact = 18.0Arms
PFdisp = Ireal/Ifund = 0.98
PFdist = Ifund/Itotal = 0.95
PFtotal = PFdisp*PFdist
PFtotal = 0.93
60
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 61
How can we reduce
(mitigate) the
harmonic current?
Drive Without DC Link Choke
• Typical ITHD
of 80 to
120%
• Sensitive to
line voltage
transients
• High peak
line currents
La.I = f( ...
150.0m
150.0m
200.0m
200.0m
162.5m
162.5m
175.0m
175.0m
187.5m
187.5m
-400.0 -400.0
400.0
0 0
-200.0 -200.0
200.0 200.0
M
hp
Motor
Load
Transformer
xfmr
% Z
Drive
DC
AC
AC
DC
Common
configuration for
drives < 5hp
NOTE: Ipk about 3x Irms
Line Reactor, Drive w/o DC Link Choke
• Typical ITHD
of 30 to 45%
• Big help for
drives
without DC
link choke
La.I = f(t...
150.0m
150.0m
200.0m
200.0m
162.5m
162.5m
175.0m
175.0m
187.5m
187.5m
-400.0 -400.0
400.0
0 0
-200.0 -200.0
200.0 200.0
Copyright © 2008 Rockwell Automation, Inc. All rights reserved. 63
M
hp
Motor
Load
Transformer
xfmr
% Z
Line Reactor
Drive
DC
AC
AC
DC
Typical values are 3% and
5% impedance
NOTE: shown is 3% LR
Drive With DC Link Choke
• Typical ITHD of
30 to 40%
• Less sensitive
to line transients
La.I = f(t...
150.0m
150.0m
200.0m
200.0m
162.5m
162.5m
175.0m
175.0m
187.5m
187.5m
-400.0 -400.0
400.0
0 0
-200.0 -200.0
200.0 200.0
Copyright © 2008 Rockwell Automation, Inc. All rights reserved. 64
NOTE: Ipk about 1.5x Irms
M
hp
Motor
Load
Transformer
xfmr
% Z
Drive
DC
AC
AC
DC
DC Link
Choke
Line Reactor in Addition to a DC Link
Choke
• Typical ITHD of
20 to 35%
• Big help for
drives w/o DC
link choke
• 0.75 - 0.95 PF
La.I = f(t...
150.0m
150.0m
200.0m
200.0m
162.5m
162.5m
175.0m
175.0m
187.5m
187.5m
-400.0 -400.0
400.0
0 0
-200.0 -200.0
200.0 200.0
M
hp
Motor
Load
Transformer
xfmr
% Z
Line Reactor
Drive
DC
AC
AC
DC
DC Link
Choke
Typical values are 3%
and 5% impedance
NOTE: shown is 3% LR
Passive Harmonic Filter
• Typical ITHD of
4 to 7%
• 0.3 to 1.0 PF
Ia = f( S,...
-25.00m
-25.00m
24.90m
24.90m
0
0
-20.00m
-20.00m
-10.00m
-10.00m
10.00m
10.00m
20.00m
20.00m
-150.0 -150.0
150.0
0 0
-100.0 -100.0
-50.0 -50.0
50.0 50.0
100.0 100.0
M
hp
Motor
Load
Transformer
xfmr
% Z
Passive Filter
Drive
DC
AC
AC
DC
DC Link
Choke
Active Harmonic Filter
• Typical ITHD of 3
to 6%
• 0.9 - 0.99 PF
Ia = f( S,...
-25.00m
-25.00m
24.90m
24.90m
0
0
-20.00m
-20.00m
-10.00m
-10.00m
10.00m
10.00m
20.00m
20.00m
-150.0 -150.0
150.0
0 0
-100.0 -100.0
-50.0 -50.0
50.0 50.0
100.0 100.0
M
Drive
hp
Motor
Load
Transformer
DC
AC
DC Link
Chokexfmr
% Z AC
DC
Ifund Ifund + Iharm
Iharm
Active Filter
AC
DC
Current from Transformer
Multi-Pulse VFD
• 12-Pulse
Typical ITHD of
9 to 12%
• 18-Pulse
Typical ITHD of
4 to 5%
• 0.90 - 0.99
PF
Ia = f( S,...
-25.00m
-25.00m
24.90m
24.90m
0
0
-20.00m
-20.00m
-10.00m
-10.00m
10.00m
10.00m
20.00m
20.00m
-200.0 -200.0
200.0
0 0
-100.0 -100.0
100.0 100.0
M
hp
Motor
Load
Transformer
xfmr
% Z
Multi-Phase
Transformer
Drive
DC
AC
AC
DC
DC Link
Choke
3 9
Multi-Set
6 pulse bridge
Spectrum – 3ph Diode Bridge
0
10
20
30
40
50
60
70
80
90
100
1 3 5 7 9 11 13 15 17 19 21 23 25
69 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Harmonic Number
% A
mp
litude
Spectrum – 12 Pulse Diode Bridge
70 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Harmonic Number
% A
mp
litude
0
10
20
30
40
50
60
70
80
90
100
1 3 5 7 9 11 13 15 17 19 21 23 25
Spectrum – 18 Pulse Diode Bridge
71 Copyright © 2011 Rockwell Automation, Inc. All rights reserved.
Harmonic Number
% A
mp
litude
0
10
20
30
40
50
60
70
80
90
100
1 3 5 7 9 11 13 15 17 19 21 23 25
Active Front-End
• Typical ITHD of 3
to 5%
• Regen
• 0.8 – 1.0 PF
Lx1.I = ...
145.0m
145.0m
195.0m
195.0m
150.0m
150.0m
162.5m
162.5m
175.0m
175.0m
187.5m
187.5m
-200.0 -200.0
200.0
0 0
-100.0 -100.0
100.0 100.0
M
hp
Motor
Load
Transformer
xfmr
% Z
Drive
DC
AC
AC
DC
Notch Filter
Popular Harmonic Mitigation
Choices
73
• 18-Pulse - widely accepted – Works well – Has become more expensive
• Passive Filters – Suited to lower power ratings <100 hp – Numerous suppliers
• Active Filters – Versatile – used for single drives or multiple drives
• AFE – Increasing in interest and use – Feature of line regeneration capability makes it
attractive
What Did We Learn?
• What are harmonics? – Distorted waveform, sine
wave element that make up distorted waveform
• How are they measured? – FFT RSS THD TDD PCC
• Why do drives produce line current harmonics?
– Non Linear Load, 6 pulse rectifiers
• How much is too much?
– Voltage distortion greater than 5%
• How do we apply IEEE-519?
– Limits guidelines
• How do harmonics vary with load?
– Voltage distortion increase as Iharm increases as a % of maximum available current
• How can the drive harmonics be reduced?
– DC link choke, Line reactor, Passive filter, active filter, xfmr config, multipulse converter, active front end
• What about Power Factor?
– Disp pf high, total pf is dist pf * disp pf ( lower than disp pf)
• Total pf proportional to Ithd
– Be careful with passive filters and leading pf
• What about gensets ( Generators )?
– Increase in Vthd due to greater impedances,
– Voltage regulation issues when applied to drives
Copyright © 2011 Rockwell Automation, Inc. All rights reserved. 74
HARMONIC SOURCE
PLC
EQUIPMENT
TELEPHONE
EQUIPMENT
DATA
PROCESSING
CENTER
PCC
IH
PQ02 – Power Quality and Monitoring..
PQ03 – Using Test Eqipment to Detect and Measure PQ Issues
PQ04 – Understanding Power Monitoring
PD02 – Power Quality and Monitoring
MC04 – Installation Considerations for VFD’s
You can find these products in the
Solution Area SA01
Related Content at the Expo
PQ01 - Harmonic Solutions for VFD’s
76
Dave Dahl – Rockwell Automation Randy Keranen – Werner Electric Drives, Motors, and PowerMonitor Product Manager [email protected]
Thank You!
Matrix AP
Harmonic
Filter