- Harmonics are multiples of the supply frequency that are produced by non-linear loads such as AC to DC converters. They can cause overheating, overloading, and failures in electrical equipment. - Common sources of harmonics are computers, electronic ballasts, variable speed drives, UPS systems, and rectifiers. Harmonics can lead to issues like overloading of neutrals, overheating of transformers, and tripping of circuit breakers. - Solutions to harmonics include passive filters using inductors and capacitors, active harmonic filters that inject compensating currents, and improving power factor using capacitors or active power factor correction.

1. –© Fuji Electric India Pvt., Ltd. All rights reserved. –1
NAME: MR. RAJESH. T
ZONE: SOUTH-2
LOCATION: BANGALORE

2.  Harmonics
Basics of Harmonics
Causes and Effects
 Power Factor
Effect on P.F
 Limits of harmonics
 Solutions
Passive Filter
Active Filters
 Active Harmonic Filter Details
Harmonics & Power factor

3.  Harmonics are multiples of the supply fundamental
frequency, produced by ‘non-linear’ loads such as the AC to
DC power conversion circuits.
 For example, on a 50Hz supply,
- the 3rd harmonic is 150 Hz,
- the 5th harmonic is 250 Hz,
- the 7th harmonic is 350 Hz, etc.
 These are called ‘integer harmonics’
i.e. exact multiples of the supply frequency.
Harmonics

4. Main sources of voltage and current harmonics are,
 Computers & Electronic ballasts
 Rectifiers
 AC & DC drives
 UPS systems
 Arc furnaces & SCR temperature controllers
 Battery chargers & Rectifiers
Sources of Harmonics

5. Instead of drawing continuous current from the supply, the
computer SMPS draws pulses of current which contain large
amounts of third and significant high frequency components
THD = 80 to 140%
Computer & Electronic Ballast

6.  Variable Speed Drives
 UPS
 Battery Chargers
& Rectifiers
6 pulse Rectifier
THD = 30 to 60%
Rectifiers

7. THD = 10 to 15%
Rectifiers
12 pulse Rectifier

8.  Harmonic currents causes problems on both
the Supply system and within the installation.
 The effects and the solutions are different and need
to be addressed separately.
 The measures that are appropriate to control the effects
of harmonics within the installation may not necessarily
reduce the distortion caused on the supply and vice versa.
Harmonic Causes & Effects

9.  Problems caused by harmonic currents
 Overloading of neutrals
 Overheating of transformers
 Nuisance tripping of circuit breakers
 Over stressing of power factor correction capacitors
 Skin effect
 Problems caused by
harmonic voltages
 Voltage distortion
 Zero-crossing noise
Common problem caused by Harmonic

10. As source has some
impedance, harmonic load
currents give rise to
harmonic voltage distortion
on the voltage waveform
(this is the origin of ‘flat
topping’).
There are two elements to
the impedance :
Voltage distortion by non linear load
that of the internal cabling from the point of common coupling
(PCC), and that inherent in the supply at the PCC,
e.g. the local supply transformer.
Problems caused by Harmonic voltage

11. The distorted load current drawn by the non-linear load
causes a distorted voltage drop in the cable impedance.
The resultant distorted voltage waveform is applied to all other
loads connected to the same circuit, causing harmonic
currents to flow in them - even if they are linear loads.
When considering the magnitude of harmonic voltage
distortion it should be remembered that, when the load is
transferred to a UPS or standby generator during a power
failure, the source impedance and the resulting voltage
distortion will be much higher.
Problems caused by Harmonic voltage

12. Summary : Harmonics effect & causes
 Overheating and failure of electric motors
 Overloading, overheating and failure of power factor correction
capacitors, distribution transformers and neutral conductors.
 Reduction of efficiency of power generation, transmission, and
utilization
 Aging of the installation of electrical plant components and
shortening of their useful life
 Malfunctioning and failure of electronic equipment Excessive
measurement errors in metering equipment
 Spurious operation of fuses, circuit-breakers and other protective
equipment
 Voltage glitches in computers systems resulting in lost data
 Electromagnetic interference with TV, radio, communication &
telephone systems
 Damage and disruption to standby generators and associated AVR
control equipment

13. For Non linear load
PFdisp = is a displacement power factor
PFdist = is a distortion power factor or Harmonic Power factor
Distortion factor

14. 0.5
0.55
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
1
10 30 50 70 90 110 130
PowerFactor
THDi
THDi Vs Power factor

15. Load pf disp THDi pf dist pf true
Ceiling Fan 0.999 1.8 1.000 0.999
Fluorescent
Lamp
0.956 39.5 0.930 0.889
Television 0.988 121.0 0.637 0.629
Desktop
Computer
and Printer
0.999 140.0 0.581 0.580
Common single phase residential loads
Power factor & Current Distortion

16. Due to poor power factor there is ;
 The undesired demand on transmission capacity
 Increased Energy losses
 The additional current causes additional voltage drops
in the distribution system. Reactive current flowing
in a resistance causes a real power loss.
 Penalty imposed by the electricity boards
Causes and Effect of Power factor

17. Limits as per IEEE 519

18. Solutions
Harmonics and Power Factor
Improvement Methods

19. Solutions
Passive filters
 Series inductor
 Phase multiplication methods
 Tuned filters
Active harmonic filters
 Series filters
 Shunt filter
 Hybrid filter (combination of active and passive filter)
Harmonics Improvement
 Capacitors
 Active harmonic filters
Power Factor Improvement

20. Product Information
Active Harmonic Filter (AHF)
IORA 3000

21. Contents
 Working principle of Active Harmonic Filter
 Introduction : AHF solution
 Features and Specifications
 Performance Results
 Applications
 Comparison between Active and Passive filters

22. Working Principle of AHF
 Input source current is sensed by DSP
 DSP calculates harmonic components of the input current and
reactive input power. Counter harmonics and reactive power
control is generated by the DSP and fed to power circuit
 With this harmonics and reactive power is compensated by Active
filter
Fundamental only
Supply
Active
Filter
icompensation
idistortion
Load

23. Introduction to AHF Solution
 It is controlled by using 32 bit
DSP operating at high freq.
Power circuit is built by using
high speed IGBTs
 It works in shunt
with the load
 Works on the principle
of synchronous rotating
reference frame
i.e in DQ co-ordinates
 It improves stability
 This helps in increasing
harmonic attenuation ratio
and better PF correction

24. Features & Specifications
 Closed loop active filter with source current sensing
 High attenuation up to 96% of individual harmonics
 Programmable selective harmonic elimination
 PF compensation, leading as well as lagging
 Required PF is user settable to any value from 0.7 to unity
 Selection between PF and harmonic compensation
 Remote monitoring and diagnosis
 IGBT based inverter design
 3 units can be used in parallel

25.  Self current limited, if overloaded
 Current limit is automatically modified if used at higher ambient
temperature without shutting down.
 Complies to IEEE519 for low frequency harmonics
 For EMI complies to IEC62040-2 for CLASS A restricted use
 Tough Screen TFT display
Features & Specifications .....contd.

26. Remote Monitoring & Diagnosis
 All front display parameters including waveforms
can be monitored through PC.
 Supports MODBUS protocol for integration
with MODBUS compliant software (optional)
 Web enabled (optional)
i.e. Parameters can be monitored through internet.
 Potential free contacts
for monitoring the status of the filter.

27. Performance Results
 6 pulse UPS load without any passive filter
 At I/P supply – Nominal & High

28. Performance Results for 6 pulse UPS with 100A filter
 Input Current 164 A
 Voltage 217 V
 VTHD 4.8 %
 ITHD 27.4 %
 PF 0.87
 Power kVA 106.5
 Power kW 92.7
Parameters Without filter

29. With filter - only Harmonic compensation
 Input Current 146A
 Filter Current 48A
 Voltage 221 V
 VTHD 3.7 %
 ITHD 4.0 %
 PF 0.92
 Power KVA 96.79
 Power kW 90
Performance Results for 6 pulse UPS with 100A filter

30.  Input Current 135 A
 Filter current 95 A
 Voltage 223V
 VTHD 2.2 %
 ITHD 3.9 %
 PF 1.00
 Power KVA 90.30
 Power kW 90.30
With filter - Harmonic & PF compensation
Performance Results for 6 pulse UPS with 100A filter

31. Parameter A V
(P-N)
THD
V
THD
i
PF kVA kW Filter
A
Without AHF 164 217 4.8 % 27.4 % 0.87 106. 5 92.7 --
Without Active Filter Harmonics compensation Harmonics +pf compensation
Performance Results for 6 pulse UPS with 100A filter
THDi + pf 135 223 2.2 % 3.9 % 1.00 90.3 90.3 95

32. With high input voltage
Performance Results for 6 pulse UPS with 100A filter
 Without filter
THDi 34 %
Vin 251
THDv 8.2 %
Iin 161 A
 With filter
THDi 4 %
Vin 254
THDv 2.2 %
Iin 119
PF 0.99

33. Applications
 To reduce harmonics and improve power factor of
UPS, Rectifiers, AC & DC drives etc
 To improve PF of motor loads i.e inductive loads
 Can be used at the output of UPS, to reduce harmonic
effects on UPS and increase available capacity.
UPS will supply only fundamental and active power.
 Can be connected at the input source

34.  Can be used as Hybrid filter
i.e. can be used along with passive filter and
capacitor filter to reduce size and make it cost effective
 Can be used one at the input of multiple UPSs.
e.g 60 A filter is sufficient for 160 KVA UPS. The same
can be used for 4 nos of 40 KVA.
For higher ratings of UPS, same filter can be used,
with higher THDi. At lower practical load level, this
suffices the purpose.
Applications......contd.

35. Comparison between Active & Passive filters
Parameters Capacitor filter Tuned filter Active filter
No load
condition
Imposes capacitive PF
when load is reduced.
Contactors are required to
compensate for leading pf.
Imposes leading PF at
fundamental frequency. So
not suitable for generator
source. Compensated filter
is required for generator.
Performance is tuned at
full load
No capacitive PF at no load.
Smooth PF compensation.
No problem to Generator
source.
Performance remains
constant over load variation
Selectivity
And harmonic
Compensation
No selectivity Physical components are
required to be changed
Stability through software.
Cost vs. performance is
easily possible. This makes
it more cost effective and
flexible
Capacity
increase
Possible by adding more
capacitor
Redesigning is required for
change of load.
More units can be added
later on for increasing
capacity
Safety To take care of resonance
problem, lot of fuses must
be used. Also resonance
causes failure of other
sensitive circuits
Breakers and fuses must
be added per tuned filter.
Also transient voltage
absorbers must be used to
avoid failure of other
circuitry in case of
resonance
Only one set of Breakers
and fuses are required for
all harmonics
Power loss Low loss More loss Moderate losses

36. Comparison between Active & Passive filters
Parameters Capacitor filter Tuned filter Active filter
Type Passive Passive IGBT based digitally controlled
Compensation
Only compensates
power factor
Compensates Harmonic Multiple
tuned filters are required, one for
each harmonic
Compensates PF and
Harmonics. One filter can
compensate multiple
harmonics simultaneously
Suitability
Not suitable in case
of more voltage
distortion and
current distortion
Performance varies over frequency
variation and variation in voltage
distortion. Performance is
dependent on load level
Performance remains constant
over frequency and voltage
variation.
Suitable in any type of
environment
Resonance
Possibility of
resonance. This
results in premature
failure of capacitor.
Possibility of resonance if tuned at
higher frequency. Performance
depends on source impedance
No possibility of resonance.
Stable operation
Size and
weight
Bulky in size
Bulky in size when multiple
harmonics are to be compensated
Light weight. Size does not
change even if required to
compensate more harmonics
Life
Limited life in case
of more voltage and
current harmonics
More life as compared to capacitor
filter
Longer life, since performance
remains constant and
resonance is avoided
Cost Cheap
Costlier as compared to capacitor
filter
Initial cost is more as
compared to both the filters

37. Thank you
for further details
Email: rajesh.t@fujielectric.com
Phone : 9342561609 / 9886682752