Download low harmonics solutions technical seminar

LOW HARMONICS SOLUTIONS
FREEMAQ SERIES
February 2014
1
Harmonic Causes
2
Harmonic Effects
3
Useful Formulae
4
EMC – THD Standards
5
PE Low Harmonics Techn.
6
SD700FA AHF
HARMONICS CAUSES
Three-phase loads:
 n = (k·6 ± 1): 5, 7, 11, 13, 21, ….
• Variable speed drives, rectifiers, Electrical arcfurnaces lifts, …
• Do not appears tripleN harmonics.
• 3 wires AHF cancellate harmonics
Single-phase loads:
 TripleN & n = (k·6 ± 1): 3, 5, 7, 9, 11, 13, 15 …
• PC’s, faxes, dimmers, LED lighting, phone
chargers, Arc welding machines, etc…
• Produce high neutral currents
• TripleN harmonics are cancelled with 4 wires
AHF
Where:
k = 1, 2, 3, 4, 5...
HARMONICS EFFECTS
 Power factor reduction. Losses and inefficiency of the electrical
system.
 Conductor losses and transformer overheating (skin effect)
 Damage to capacitors and resonance. (High frequency current
flow through low impedance paths overloading capacitors)
 Transformer and neutral conductor overload due to excessive
zero-phase currents
 Motor Overheating. Negative rotation sequences in motors
 Nuisance tripping of protections ( fuses, circuit breakers,
relays, etc..)
 Failure of stand-by diesel generating sets
Voltage
RMS Current
Apparent Power S= V ·I
USEFUL FORMULAE
 Displacement Power Factor (cos )
𝑃 (𝑘𝑊)
𝐷𝑃𝐹 = 𝑐𝑜𝑠 𝜑 =
𝑆 (𝑘𝑉𝐴)
 Total Harmonic current Distortion THDi (%)
𝑇𝐻𝐷 =
𝑛=∞ 2
𝑛=2 𝐼𝑛
𝐼1
 Power factor (PF)
𝑃𝐹 =
1
1 + 𝑇𝐻𝐷𝐼 2
· 𝑐𝑜𝑠 𝜑 =
 Apparent power
𝑆𝑇 =
𝑃2 + 𝑄 2 + 𝐷 2
𝐼50𝐻𝑧
· 𝑐𝑜𝑠 𝜑
𝐼𝑟𝑚𝑠
USEFUL FORMULAE
Utility transformer
S (kVA), Zout (%), Vout (V)
Zsc
Main Feeder
L (m), Wire size (mm 2), Material (Cu or Al),
Conductors (#)
PCC
Zt
User transformer
S (kVA), Zout (%), Vout (V)
IPC1
Zf’
IPC1
Distribution Feeders
L (m), Wire size
Conductors (#)
(mm 2),
Material (Cu or Al),
Zf2’
Zf2’’
Zf2’’’
IPC2
Non- Linear Loads
IPC2
P (kW), H (%), cos φ
Zf3’
Linear Loads
P (kW), Cos φ
IPC3
IPC3
Zf4’
PCC: Point of common coupling
IPC Internal point of coupling
Zf4’’
Zf4’’’
THDu levels evolution
Private Grid
THDi levels evolution
Public Grid
PCC
ELECTROMAGNETIC COMPATIBILITY (EMC) | INTRODUCTION
EMC
Electromagnetic Compatibility
EMS
Electromagnetic Susceptibility
Amplitude
ENVIRONMENT CLASS
EMI
Electromagnetic Interference
Device Immunity level
Minimum Immunity level
COMPATIBILITY MARGIN
Maximum Emission level
Device emission level
Frequency spectrum
ELECTROMAGNETIC COMPATIBILITY (EMC) | INTRODUCTION
EMC
Electromagnetic Compatibility
EMI
Electromagnetic Interference
EMS
Electromagnetic Susceptibility

Low
frequency
Medium
Frecuency
F <150 kHz
150 kHz< f < 30MHz
 THD
 Flicker
 Conduced
High
Frecuency
f > 30MHz
 Radiated
IEC61800-3





Radio Frequency
 Conduced
 Radiated
Surges
Electrical fast transients
Electrostatic discharges
THD
Voltage dips and
interruptions
ELECTROMAGNETIC COMPATIBILITY (EMC) | STANDARDS
 CE marking for variable speed drive requires compliance with directive EMC 2004/108/CE
EMC 2004/108/CE
IEC61800-3
 EMC 2004/108/CE requires compliance with standard IEC61800-3
 IEC61800-3 states that the manufacturer shall provide the current harmonic level under
certain conditions.
THDv
¿Compatibility levels?
IEC61000-2-2
IEC61000-2-4
 IEC61000-2-2: Public Low Voltage
Power Supply Systems
 IEC61000-2-4: Industrial and nonpublic networks.
 Individual VHD and THDv (%)
depending on the 3 environmetal
class defined
IEC61000-3-4
IEC61000-3-12
 Public networks up to
600V
 THD and PWHD up to:
 IEC61000-3-4 <16A
 IEC61000-3-12 < 75A
IEEE519 - 1992
THDi
 Recomended
practives
and
requirements for harmonic control
in Electrical Power Systems.
 Individual VHD and THDv (%)
depending on Isc/IL
 Individual CHD and THDI (%)
depending on Isc/IL
ELECTROMAGNETIC COMPATIBILITY (EMC) | IEC61800-2-4
CLASS
CLASS 1
CLASS 2
CLASS 3
DESCRIPTION
THDv (%)
Location where equipment that is very sensitive to disturbance. This class applies to
protected feeders and has compatibility levels that are lower than the level of the public
supply system
5%
This class generally applies to PCCs (Points of Common Coupling) with the public supply
system and to IPCs (Internal Points of Coupling) with industrial or other private supply
systems.
8%
This class applies only to IPCs (Internal Points of Coupling) in industrial environments.
It has higher compatibility levels for some disturbance variables than Class 2. For example,
this class should be considered when one of the following conditions applies:
• The main part of the load is supplied via converters;
• Welding machines are used;
• Large motors are started frequently;
• Loads vary quickly
Note: IEC61800-2-4 establish individual harmonic voltage distortion
10%
ELECTROMAGNETIC COMPATIBILITY (EMC) | IEC61800-3-12
Current emission limits for balanced
three-phase equipment < 76A
Admissible individual harmonic current In/I1 (%)
Admissible harmonic
current distortion factors %
Minimal Rsce
I5
I7
I11
I13
THD
PWHD
33
10.7
7.2
3.1
2
13
22
66
14
9
5
3
16
25
120
19
12
7
4
22
28
250
31
20
12
7
37
38
350
40
25
15
10
48
46
ELECTROMAGNETIC COMPATIBILITY (EMC) | IEE519 - 1992
Individual and total voltage distortion
limits at PCC (THDv)
Isc/IL
Permissible values for
each individual harmonic
voltage
Individual and total current distortion
limits at PCC (THDi):
Harmonic Order
Typical Users
Special customers with special
agreements
Isc/IL
<11
11≤h<17
17≤h<23
23≤h<35
35≤h
THDi
<20*
4.0
2.0
1.0
0.6
0.3
5.0
10
2.5 – 3 %
20
2.0 – 2.5 %
1 – 2 large loads
20<50
7.0
3.5
2.5
1.0
0.5
8.0
50
1.0 – 1.5 %
A few high-output loads
50<100
10.0
4.5
4.0
1.5
0.7
12.0
100
0.5 – 1 %
100<1000
12.0
5.5
5.0
2.0
1.0
15.0
1000
0.05 – 0.1 %
>1000
15.0
7.0
6.0
2.5
1.4
20.0
THD (voltage)
5 – 20 medium-output loads
A large number of low-output loads
Special
applications
General system
Dedicated
system
3%
5%
10%
Isc: Maximum short circuit current @ PCC
IL : Maximum current consumption by the load @ PCC
SD700 FREEMAQ FR
SD700 FREEMAQ FL
SD700 FREEMAQ FA
SD700 KOMPAKT
SD700
¿WHAT SHOULD I DO?
The selection of the appropriate technology shall be based in the following items:
 Is it a new or retrofit project?
 How many and which is the individual power rating of the harmonics sources?
 What are the requirements for reactive energy compensation (cos )?
 Is there any presence of tripleN harmonics (3, 9, 15,…)?
HARMONICS MITIGATION TECHNOLOGIES
DC CHOKES
CHOKES 3%
MULTIPULSE
SD500, SD700F1&2
SD700 series
SD700 series 12,18,24p
THDi <35%
THDi <15%
THDi ≈ 40%
L1
L2
L3
L1
L2
NOTCH FILTER
SD700 FREEMAQ FL
THDi <5%
AFE
SD700 FREEMAQ FR
THDi <4%
LH TECHNOLOGIES | SD700 MULTIPULSE DRIVE
 PE offers 12, 18, 24 pulses drives
 The rectifiers are shifted 30º / 15º / 7,5º
 The current harmonics generated are:
n = kp ± 1,
Where:
k = 1, 2, 3, 4, 5...
p = number of pulses
12 pulses;
18 pulses;
24 pulses;
11, 13, 23, 25, 35, 37, 47, 49, …
17, 19, 35, 37, 53, 55, ….
23, 25, 47, 49,…
6p THDi ≈ 35%
12p THDi ≈ 15%
18p THDi ≈ 9%
24p THDi ≈ 5%
Consider that...
THDi in the low voltage side of the
transformer will remain being 35%
(same as 6pulse drive)
LH TECHNOLOGIES | PASSIVE TUNNED FILTERING
Zg
L1
L2
C1
C2
1st
5th
7th
Grid Impedance (Zg) Variation
f5th
f7th
 Tunned Filters designed for 5th or 7th Harmonic
cancellation with a fixed Grid Impedance ( Zg)
 Variation on Zg → Increase THDi
 Variation on Zg → May cause Resonance
 Valid for original facilities, retrofit projects
modify the conditions.
1st
5th
7th
LH TECHNOLOGIES | SD700FL NOTCH FILTER
L1
L2
Zg
L3
C1
SD700FL
1st
5th
7th
 THDi < 5%, below the limits defined in IEEE519 for all ISC/IL.
 LCL Notch Filters designed for General Harmonic attenuation and independent from the Grid
Impedance ( Zg)
 Variation on Zg → Do NOT affect to THDi . ZL1>> Zg
 Built in with robust electric components
 Never cause resonance
LH TECHNOLOGIES | SD700FR ACTIVE FRONT END
L1
L2
Zg
C1
SD700FR
 THDi < 5%, below the limits defined in IEEE519 for all ISC/IL.
 Cos Φ = 1.0 adjustable at any load condition.
 Energy Regeneration for energy savings and built in Energy registers
 Invariable Motor voltage against input voltage drops due an adjustable DC Voltage
 Less Power Wiring and significant space savings
 No additional installation cost
LH TECHNOLOGIES | SD700FA ACTIVE HARMONIC FILTER
SD700FA
Múltiple 6 pulse drives and
other distortion sources
 Works as a current source monitoring the load current or the line current at the point of
interconnection, and injects the inverse current wave that cancels the harmonic distortion
 THDi control at any load: Selective harmonic cancellation or full spectrum harmonic cancellation
at any load conditions
 Cos Φ = 1.0: It allows the dynamic control of the displacement power factor.
 Competitive solution and small footprint for retrofits projects.
 Centralization of the harmonics cancellation leads to a more cost-competitive solution
SD700FA ACTIVE HARMONIC FILTER | CONNECTION
 An open loop configuration measures the load current and injects the inverse current harmonic
wave form that cancels the harmonic distortion
 A closed loop configuration measures the line current at the point of interconnection and injects
inverse current harmonic to reach the target established by the user.
SD700FA ACTIVE HARMONIC FILTER | SELECTIVE ALGORITHM
=
+
 By setting the selective harmonic cancellation you will be
able to compensate in perfect opposite phase up to 6 individual
harmonics simultaneously up to 25th harmonic (Depending on
the switching frequency).
 The user can individual set the final content of each individual
harmonic in %.
H5
H7
H11
H13
H17
…
10%
10%
4.5%
4.5%
4%
…
SD700FA ACTIVE HARMONIC FILTER | FSC ALGORITHMS
+
 By setting the full spectrum harmonic cancellation the unit
will not be focused on a specific harmonic number. Any
harmonic content will be cancelled by injecting an opposite
phase current wave form that results from subtracting the
fundamental (50Hz) current wave.
=
SD700FA ACTIVE HARMONIC FILTER | ZERO-SEQUENCE HARMONICS
 Zero-sequence harmonics or tripleN are the odd number of the multiple of three harmonics
(3,9,15,…) caused by single phase loads (single-phase welders, low consumption lighting,
computers, etc..)
 TripleN harmonics circulate in phase in all three phases. Since the current in the neutral is
equal to the sum of the currents in the phases, the neutral current is In= 3·I3
 SD700FA has no neutral connection and does not filter zero-sequence harmonics. So
alternative filtering techniques can be used (Star-delta transfomer, Zig-Zag inductor, 4Wires
filter).
SD700FA ACTIVE HARMONIC FILTER | SELECTION
 SD700FA is a 3 wire Active Harmonic Filter (AHF) ranging from
100A to 630A. The current rating is expressed in RMS current
value.
 The RMS value of a given harmonic spectrum is obtained by
the following formula:
𝐼𝑅𝑀𝑆 =
𝐻5 2 + 𝐻7 2 + 𝐻11 2 + 𝐻13 2 + ⋯ + 𝐻49 2
For example:
H1 = 300Arms
H5 = 60%
=180Arms
H7 =43%
=129Arms
𝐼𝑅𝑀𝑆 =
H11 =25%
H13 =17%
=75Arms
=51Arms
1802 + 1292 + 752 + 512 = 239𝐴𝑅𝑀𝑆
SD700FA ACTIVE HARMONIC FILTER | SELECTION
 SD700FA can perform at the same time the reactive power
compensation by injecting leading or lagging current.
 Compared to traditional capacitor banks, the reactive compensation of
the SD700FA is continuous (“stepless”), fast and smooth (no transients
at switching).
 The reactive current required is added to the harmonics rms current.
The new ARMS rating is calculated as follows.
For example:
P = 800kW
Ul = 400V
DPF = cos φ = 0.90
DPF’ = cos φ’ = 0.95
IARMS_HARM=239A rms
𝑄𝐹 = 𝑃 · tan 𝜑 − tan 𝜑 ′ = 124𝑘𝑉𝐴𝑟
𝐼𝑅𝐸𝐴𝐶𝑇 =
𝑄
3·𝑈
𝐼𝐻𝐴𝑅𝑀 +𝑅𝐸𝐴𝐶𝑇 =
𝐼𝐻𝐴𝑅𝑀 +𝑅𝐸𝐴𝐶𝑇 =
=
124𝑘𝑉𝐴𝑟
3 · 400
= 179 𝐴𝑟𝑚𝑠
𝐼𝐻𝐴𝑅𝑀𝑂𝑁𝐼𝐶𝑆 2 + 𝐼𝑅𝐸𝐴𝐶𝑇𝐼𝑉𝐸 2
1792 + 2392 = 298 𝐴𝑟𝑚𝑠
SD700FA ACTIVE HARMONIC FILTER | OPERATION MODES
 The
PRIORITY
determines
the
SD700FA’s current distribution within the
available functions:
 HARMONICS: The SD700FA injects
harmonic current up to the pre-set values
(%Hi or %Iarms). Once is reached, the
remaining capacity can be used by the
next priority.
PRIORITY
HRH
HHR
HR
1st
Harmonics
Harmonics
Harmonics
2nd
Reactive
Max. Harmonics
Reactive
3rd
Max. Harmonics
Reactive
 REACTIVE: The SD700FA injects reactive
current trying to reach the pre-set cos φ.
As before, the remaining capacity can be
used by the next priority.
 MAX.HARMONICS: If the HARMONICS
levels are met, and there is some current
capacity left. The SD700FA can continue
injecting harmonic current in order to fully
cancel the harmonics.
Pre-set harmonic value
POWER ELECTRONICS
appreciate your attention
More info:
www.power-electronics.com