Harmonics mitigation solutions

Harmonics mitigation and solutions

Schneider Electric 2
I. Introduction
II. Harmonics mitigation
solution
III.Case study
lV.Conclusion
Summary

I. Introduction
II. Harmonic mitigation solution
III.Case study
lV.Conclusion

I. Introduction
●The quality of electrical power is determined by the voltage
● High-quality voltage is the best guarantee for continuous operation of
equipment
The voltage signal must be perfect
at the source...
... because distortion may occur at the
end of the line
Line impedance
Type of installation
Length of cables
Internal impedance of
equipment...
The harmonic current
from the load
Type of load
Power supply
technology

I. Introduction
III.Case study
lV.Conclusion

-1.5
-1
-0.5
0
0.5
1
1.5
=
-1.5
-1
-0.5
0
0.5
1
1.5
+
-1.5
-1
-0.5
0
0.5
1
1.5
Signal with harmonics Fundamental H1 Harmonics H2 to Hn
H1 = 50Hz Hn = n x 50Hz
THD (U or I) % = 100 x
II. What is a harmonic waveform?
●Harmonic waveform is a distortion of the normal
Sinewave
●It is characterized by its distortion level
● For voltage (THD U - Total Harmonic Voltage
Distortion)
● For current (THD I - Total Harmonic Current
Distortion)

●Waveform examples and harmonic
spectrum
● Three- phase loads
Variable speed drive
Lifts…
● Single-phase loads
● Computers
● Phones
● Lighting ...
II. Current distortion
H11 H13 H17 H19 H21 H23
0
50
100
H1 H5 H7
Danger
H7 H9 H11 H13 H15
0
50
H1 H3 H5
Danger
H17
100

II. The effects of harmonics
●Voltage distortion:
● Excessive temperature rise in motors
● Electrical noises
● Sensitive electronic equipment malfunction
●Increase in the apparent power and over-sizing of sources (UPS,
Genset, etc.), capacitors, cables...
● Derating of electrical equipment or over-sizing
● Accelerated ageing of equipment
●Flow of current in the neutral conductor and consequently in the
PEN:
● Excessive temperature rise in transformer
● Tripping of circuit breakers

M M M
Final distribution
enclosure
feeder S1 feeder S2 feeder S3
Secondary
switchboard
Main LV
Switchboard (MLVS)
feeder MS1 feeder MS2 feeder MSn
LV
Increased THDU
Increased RMS current
Non-linear current
circulating in the cables
●Voltage distortion: influence of THDI on the THDU

> Linear load without harmonics:
• Cos phi = Power factor = P/S
> Non-linear load :
• DPF = Displacement Power Factor - P1/S1 ( 50 Hz
fundamental current only)
• True Power factor = P/ST
> S = apparent powerP (W)
Q (var)φ
S (VA)
ST (VA)
D harmonic
P2 + Q2S =
P2 + Q2 + D2S =
●Increase in the apparent power and over-sizing of
sources

-6
-4
-2
0
2
0 90 180 270 360 450
Phase 1
Phase 2
Phase 3
3rd Harmonic, phase 1
Total 3rd Harmonic
●Flow of current in the neutral conductor
● The H3 harmonic currents and multiples flow in the neutral
conductor.
● The cross-sectional area of the neutral conductor must be increased
(1.7 times that of the phases for switch-mode power supplies).
I3,I9,I15

Normal or replacement
sources
Over-sizing of sources,
cables, etc.
Transformers with
different couplings
Tuned
filters
Anti-harm.
reactors
&
series filters
LD
y
Y
y
p1 = p2 p1 = p2
h5 h7
F
- The harmonics are not
eliminated.
- Very costly
2 Limits h3 and multiples.
D
d y
3 4
5 6
1
D
yn
h3 h9
2
h7 (6-pulse bridge)
5
6
Attenuates harmonics
at the tuning frequency.
Decreases THD(i).
1
3 4and attenuate h5 and
II. Harmonics mitigation solutions
●Electromechanical solutions
●Active filters

LoadMains
Filter
No capacitors
No power electronics
No batteries
No micro controllers
Unmatched reliability, same as that of a dry transformer
II. Passive filter: architecture & design
●3-phase + neutral filter
●Composed of only two elements
● 1 serial three-phase inductance
● 1 parallel three-phase inductance
Ph
N
Lo
Zo

input
output
●At A Glance:
● Zero sequence harmonic filter
● Reduces neutral currents in
commercial & industrial buildings
● Balancing of 3-phase currents
● 12-280 kVA (expandable)
● 3-phase low voltage applications
●Customer benefits
● Simple and highly reliable design
● Reduction of neutral currents by 10:1
● Compliance with harmonic standards
● Capacity upgrade by parallel
connection
● Operational savings
● Easy integration into power
distribution cabinets (Chassis Format)
● Easy sizing and installer friendly
II. Cleanwave: solution for neutral currents

II. Sizing cleanwave
●CleanWave is designed for the most demanding situations
● H3 harmonics and multiple: THDI up to 80%
● Neutral current = 1.8 times phase current
●Very easy sizing
Max power or max. Iphase
of the load
Selection of the filter of
immediately higher
power or current
25 kVA load
Selection of the
30 kVA CleanWave

II. Unbalanced load tests
Balanced Without Ph3 Without Ph2 & 3
I1 in
In in
I1 out
In out
I1 in
In in
I1 out
In out
I1 in
In in
I1 out
In out
I1: 150A
I2: 149A
I3: 151A
In: 21A
I1: 126A
I2: 126A
I3: 127A
In: 242A
I1: 126A
I2: 126A
I3: 0A
In: 201A
I1: 112A
I2: 122A
I3: 65A
In: 25A
I1: 107A
I2: 46A
I3: 46A
In: 25A
I1: 154A
I2: 0A
I3: 0A
In: 150A
Input:
In = 21 A
Output:
In = 242 A
Input:
In = 25 A
Output:
In = 201 A
Input:
In = 25 A
Output:
In = 150 A
1mv=1 A 1mv=1 A1mv=1 A

I source I load
Power
source
Non-linear
load
Active
harmonic
conditioner
I conditioner
● The active harmonic conditioner generates the harmonic currents
required by non-linear loads. These currents are opposite in phase with
respect to the current supplied by the source.
● The A.H.C is sized only for harmonic currents
● The current consumed by the load is therefore:
I load = I source + I conditioner
II. Active harmonic conditioner: architecture &
design

34
The
harmonics are
eliminated
upstream and
apparent
power is
reduced
Active
conditioner
supplies the
required
harmonics to
the load
2
CTs analyze the
harmonics
required by the
load
=
-2
-1,5
-1
-0,5
0
0,5
1
1,5
2
I. sinusoidal
-2
-1,5
-1
-0,5
0
0,5
1
1,5
2
I. load
+
I. conditioner
-2
-1
-0,5
0
0,5
1
2
1,5
Equipment is the
source of
harmonics
1
II. Reducing upstream harmonic pollution

II. Sinewave standard solution: 20-480A of
harmonic compensation
● SineWave includes everything for a simple and functional basic solution:
- EMC filter to comply with EN55011 level A and IEC 1000-4
- 7-language user interface
- Diagnostic and maintenance menu
- Basic indications by 3 LEDs
- Relay contacts for remote indications
- Terminal blocks for power and sensor connections
- Wide choice of current transformers: split or closed

● Input
• Voltage : 400 V , - 20% , + 15%
• Phases : 3-phase with or without neutral. Compatible
Operation with single phase and unbalanced load
• Frequency : 50 Hz or 60 Hz, +/- 8% auto-sensing
● Compensation characteristics
• Harmonics covered : H 2 to H 25
• Type of compensation : Harmonics - cos phi - mixed (Hn + cos)
• Compensation mode : Overall or selective (specific harmonics)
• Attenuation ratio : >10 at full load ( THDI)
• Cos phi correction : Up to 1
• THDU reduction : According to the installation parameters, THDU
reduction will be determinated by the SITE AUDIT
• Response time : < 40 ms in overall current compensation mode
• Overload : Automatic current limitation
II. Sinewave features

-2
-1,5
-1
-0.5
0
0.5
1
1,5
2
-2
-1,5
-1
-0.5
0
0.5
1
2
1,5
I phase = 48 A
THDI = 81%
I neutral = 42 A
S = 10.6 kVA
Power factor = 0.77
Cos phi 1 = 0.99
Mains current without
active conditioner
Mains current with
active conditioner
I phase = 38A (-21%)
THDI (reduced by a factor of 24) = 3.4%
I neutral = 2.6 A
S = 8.4 kVA
Power factor = 1
Cos phi 1 = 1
II. Example: Variable Speed Drive load

THDI = 92.6%
PF = 0.73
2.9%
1.0
Reduction of 27% in the line RMS current
Harmonic current without SineWave Harmonic current with SineWave
0
20
40
60
80
100
120
H1
H3
H5
H7
H9
H11
H13
H15
H17
H19
H21
0
20
40
60
80
100
120
H1
H3
H5
H7
H9
H11
H13
H15
H17
H19
H21
Test Results of a 60 A Active Conditioner
II. Example: Variable Speed Drive load

● Robust design suitable for heavy industrial
applications
● IP54 protection enclosure is standard
● Full EMC compliance with 89/336EEC,
conforms to IEC/EN 60439-1, EN61000-6-4
class A, EN61000-6-2 standards
● Current output ratings of 50 A, 100 A or 300
A
● Can be paralleled up to 10 units in any rating
combination
● Ultra fast response time (1/2 cycle)
● Cancel harmonic up to 50th order
● ABS Certified for Marine applications
II. Accusine solution

● Input
• Voltage : 208-480V, - 10% , + 10%; auto sensing
• Phases : 3-phase, 3-wire with or without neutral.
Compatible Operation with single phase
and unbalanced load
• Frequency : 50 Hz or 60 Hz, +/- 5% auto-sensing
● Compensation characteristics
• Harmonics covered : H 2 to H 50 (no filtering on neutral conductor)
• Type of compensation : Harmonics - cos phi - mixed (Hn +
cos)
• Compensation mode : overall
• Attenuation ratio : 10:1 overall
• Cos phi correction : Up to unity; can also inject lagging
VARS
• THDU reduction : Guaranteed compliance with
IEEE519; UK G5/4 or
IEC 61000-2-3
• Response time : < 10 ms
• Overload : Automatic current limitation
II. Accusine features

●Safe and reliable AC electrical distribution systems
● Overloading and overheating of the neutral conductor cancelled
● Nuisance tripping of protection circuit breakers avoided
●Improved power quality
● Reduction of the THD(V)
● Cancellation of the voltage potential on the neutral conductor
●Increased lifetime of AC distribution system equipment
●Over-sizing cables, transformers and other AC distribution equipment
avoided
●Compliance of installations with harmonic standards ensured
●Improved power factor
●Lower energy expenses/bills
II. Customer benefits / active power solutions

I. Introduction
III.Case study
lV.Conclusion

●Oil platform in the North Sea with
turbine / diesel generators feeding 6 KV
network
● Mechanical resonance on the platform
when pump VFDs operated above 49 Hz
due to generator loading
● Each 1 Hz increment in pump speed
equals $6k/day incremental revenue per
pump (2003 prices)
●2 x 600 KW VFDs at 380V
● 300A AHF for each VFD
● Operating in harmonic + power factor
correction mode
● Increased pump speed by 1 Hz
III. Accusine application case study

Voltage waveform - AHF OFF
Voltage waveform - AHF ON
●THD(V) reduced from
12.6% to 6.0%
●Note high voltage
notching & distortion on
generator fed network
Current waveform - AHF OFF
Current waveform - AHF ON
●THD(I) reduced from
31.8% to 7.2%
●PF from 80.3% to
95.2%
III. Accusine application case study

I. Introduction
III.Case study
lV.Conclusion

lV. Conclusion
●Power quality issues are well worth some consideration,
●Even more so for Oil & Gas processes where the availability and quality
of Power is quite critical,
●Correct identification of the root causes of the problem is essential to
choosing and implementing the best solution right from the start => Talk
to the experts.

●Schneider Electric is your Power Quality expert
●We offer a variety of solutions and products to help identify and correct
power quality problems
●Investing in power quality will improve both your operations and profits
The 3 main messages

Harmonics mitigation solutions

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