Individual Harmonic Display in % of
voltage and current
Individual Harmonic Display in magnitude
for voltage and current
Total demand distortion (TDD)
Measures upto 31st Harmonics
Suitable for continuous harmonic
monitoring
RS485 Communication port with
MODBUS-RTU protocol
Derating of Transformers, cables,
breakers can be decided
Effects of the mitigating devices / Filters
can be quantified
Introduction:
Major parameter affecting the Power Quality is the presence of harmonics in the
Power System. Harmonic Currents are generated by Non-linear loads in the Power System as
detailed in Appendix - 1. Harmonic currents so generated cause distortion in voltage in turn causes
further harmonic currents in good Linear loads such as Transformers, Induction motors, Heaters and
Capacitors. Additional Harmonic currents in the linear loads further distort the voltage. Finally
harmonic currents originated in the non-linear load are multiplied and spreaded to all circuits and
components of the Power System creating a lot of undesirable effects. Effects of Harmonics are
detailed in Appendix - 2. There are a lot of international standards specifying the limits for current and
voltage Harmonics as detailed in Appendix - 3 for various system voltages for trouble free running of
the equipments with minimum losses in the Power System.
Need Of Harmonic Measurement:
To know the level of Harmonics generated by the nonlinear
loads and to know the total harmonics in the particular feeder, transformer or at the point of
commencement of supply, a good Harmonic Indicator with reasonable accuracy is required to
mitigate the Harmonics to the limit specified by the standards. As of now, expensive Power Flow
study is to be conducted for a specific time which requires experts for measurement and analysis.
This method does not reveal the details for other times as the Harmonics present will vary with load
and other power supply situations with EB or DG. Hence a sample measurement will not be
adequate to design the mitigating devices or any alternate methods. A simple low cost panel
mounted Harmonic Indicator with reasonable accuracy will be immensely useful to address all the
issues created by Harmonics. ICD has developed such a meter to indicate both voltage and current
harmonics present. Individual and total Harmonic currents are indicated in magnitude as well as in
percentage of fundamental.
GENERAL DESCRIPTION:
Input to the ICD Harmonic Indicator is 3 voltage signals and 3 current
signals from 3 phase supply with suitable PT's and CT's. Advanced microcontroller is used to
compute all the indicated values with better accuracy. Meter is tested at Government Approved
Laboratory for Total Harmonics. RS 485 communication facilitates data acquisition for analysis.
Applications
To measure the harmonics at the non
linear load for equipment selection and
finalize the operating method of the
load
To measure the harmonics in the
branch circuit where the non-linear load
is connected along with other
neighboring linear loads, to safeguard
the linear loads by suitable filters /
mitigating devices
To measure the harmonics at the
Transformer secondary to safeguard the
transformer and other connected loads
by suitable filters and mitigating devices
To measure at the point of
commencement of supply to ascertain
that the presence of harmonics is within
statutory limits stipulated by EB.
To measure the harmonics at the DG
bus to ascertain the generated voltage
is within the specified harmonic level
To measure the harmonics at APFC
panels to safeguard the capacitors and
to know the harmonic amplification due
to parallel resonance
Technical Specification
MEASURED QUANTITIES
Parameter Shown :1) 3 Phase Voltage
2) 3 Phase Current
3) THD in % for R,Y,B Voltage and
R,Y,B Current
4) Individual Harmonic Display (2-31st)
in percentage as well as magnitude
for R,Y,B voltage and R,Y,B current
5) TDD in % for R,Y,B voltage and
R,Y,B current
RATINGS
Voltage Range : 80V to 520V AC line to line for LT
25V to 140V AC line to line for HT
Standard Current : 1A / 5A
Max. Current : 1.5A / 7.5A
Frequency Range : 40.00 to 60.00 Hz (Fundamental)
Auxiliary Supply : 240V AC (-20% to +10%)
Operating Temperature : 55° C (Max.)
DISPLAY
Type : 2 Row 16 Character LCD with Backlit
Character Size : 4.35 (H) x 2.95 (W) mm
LCD Power Save Mode : Provided. When no key is pressed for 3 minutes, the LCD Backlit is
switched OFF to save power and
enhance the life of LCD. The LCD is
switched ON when any key is Pressed
KEYFUNCTIONS
Key Pad : 4 Keys Index, Shift,
Increment and Enter used for
Program mode setting and
Run mode selection
Program mode Parameters: PT Primary Voltage, CT Primary Current,Device address
Unauthorised Person Entry Protection: Provided through Password Facility
COMMUNICATIONS
Type : RS485, Ethernet
Protocol : MODBUS - RTU, MODBUS - TCP
Isolation : Provided
Traffic Status : Indicated through TXD, RXD LED
CASE AND DIMENSIONS
Enclosure : ABS Plastic
Dimension : 96(H) x 96(W) x 120(D) mm
or 96(H) x 96(W) x 80(D) mm
Cutout : 88(H) x 88(W) mm
Mounting : Flush / Panel
PARAMETERS DISPLAYED
PARAMETERS
RANGE
RESOLUTION
ACCURACY
R, Y, B Voltage (LT Meter)
180 V - 270 V
0.1 V
± 0.5% + 2 least digit
R, Y, B Voltage (HT Meter)
Primary Voltage
0.01 kV
± 0.5% + 2 least digit
Current
0 - 100 A
100 A & above
0.1 A
1 A
± 0.5% + 2 least digit
THD R, Y, B Voltage R, Y, B Current
0 - 100%
0.1%
±2% Over full scale for load above 20%
± 5% Over full scale for load below 20%
Individual Harmonic Display
(2-31st Harmonic in Percentage)
0 - 100%
0.1%
±2% Over full scale for load above 20%
±5% Over full scale for load below 20%
Individual Harmonic Display
(2-31st Harmonic in Magnitude)
Voltage
0 - 100 V
0
0.1 V
± 2% + 2 least digit
Individual Harmonic Display
(2-31st Harmonic in Magnitude)
Current
0 to Primary Current set
1 A
±2% + 2 least digit
TDD R, Y, B Voltage
R, Y, B Current
0 - 100 %
0.1%
±2% Over full scale for load above 20%
± 5% Over full scale for load below 20%
Appendix -1
ORIGIN OF HARMONICS
HARMONIC DISTURBANCES ARE CREATED BY NON-LINEAR LOADS
1) Power Electronic loads (Rectifiers,Variable speed drives, UPS systems,Invertors etc.)
2) Ferro magnetic devices (Transformers)
3) Arcing devices (Arc Furnace equipments)
Appendix - 2
EFFECTS OF HARMONICS
1) Tripping of circuit breakers and fuses
2) Overloading / decrease of life time of transformers
3) Overloading of capacitors
4) Losses in distribution equipment
5) Excessive currents in the neutral conductor
6) Malfunctioning of the electronic controls and computers
7) Measurement errors in the metering systems
Appendix - 3
LIMITS OF HARMONICS
Current Limits ,Low Voltage Systems
I-EEE -519 Maximum Odd harmonic current limits for general distribution systems 120V through 69kV
Current Limits ,High Voltage Systems
I-EEE -519 Maximum Odd harmonic current limits for general distribution systems 69.001kV through 161kV
Isc/IL
THD
Isc/IL
THD
<20
5.0 %
<20
2.5 %
20 - 50
8.0 %
20 - 50
4.0 %
50 - 100
12.0 %
50 - 100
6.0 %
100 - 1000
15.0 %
100 - 1000
7.5 %
>1000
20.0 %
>1000
10.0%
VOLTAGE LIMITS IEEE -519 VOLTAGE DISTORTION LIMITS
