This document discusses harmonic mitigating transformers (HMTs) and their use in reducing harmonic distortion in electrical systems. It begins with an introduction describing how increased use of electronic equipment has led to higher levels of harmonic distortion, which can negatively impact system reliability. It then provides details on common harmonic sources, the symptoms caused by harmonics, and how HMTs work to phase-shift and cancel harmonic currents. The document explains the construction, benefits, and appropriate markets for HMTs, concluding that they provide an effective and cost-efficient means of reducing harmonics and improving system reliability.

1. ON
BY:
Mr. Sidharth Goutam Dash
Electrical Engineering
Regd. No.: 0901106181
Submitted To:
Prof. Dr. A. Mohapatra
Prof. Dr. R.K. Jena

2. INTRODUCTION
As our world becomes even more dependent on electrical
and electronic equipment, there is an increased likelihood
that operations will experience the negative effects of
harmonic distortion.
The productivity and efficiency gains achieved from
increasingly sophisticated pieces of equipment have
a drawback: increased harmonic distortion in the
electrical distribution system.
Harmonic mitigating transformers (HMTs) are a
leading solution to eliminate these harmful
harmonics and improve your system reliability.

3. Graph-a
Graph-b

5. Sources of Harmonics
General sources of harmonics
• Power electronic equipment
(drives, rectifiers, computers, etc.)
• Arcing devices (welders, arc
furnaces, florescent lights, etc.)
• Iron saturating devices (transformers)
• Rotating machines (generators)
Most prevalent and growing harmonic
sources:
• Adjustable frequency drives (AFD)
• Switch-mode power supplies (computers)
• Fluorescent lightning

6. Symptoms of harmonics
•Over-loaded neutral conductors
•Over heated motors and transformers
•Blown fuses or breakers tripping repeatedly
•Failure of power factor correction capacitors
Timing errors in sensitive electronic
equipment

8. What do HMTs do?
HMTs are an economical solution in the
battle against the harmful effects of
harmonics.
HMTs are highly reliable devices; they
don’t have any moving parts and they are
typically energized 24/7, 365 days a year.
This means that they are always “on the
job” treating harmonics, regardless of the
level of load they are serving at a given
point in time. Whenever the HMT is
energized, it will provide harmonic
treatment.

10. A typical HMT

11. Principle of HMT
 Harmonic mitigating transformers use phase-shifting
, electromagnetic flux cancellation, and source
impedance to reduce harmonic currents in electrical
distribution systems. By reducing the amount of heat that
harmonics generate, these devices enable transformers to
operate at lower temperatures. The result is lower cooling
costs as well as longer device life and reduced maintenance.
Harmonic mitigating transformers also enable the use
of a transformer’s full capacity and ensure compliance
with harmonic limits defined by the Institute of
Electric and Electronic Engineers and other
organizations.

13. Parts of a HMT
Usually a HMT consists
of five parts
 Core & Coil Assemblies
 Taps
 Electrostatic Sheilding
 Wiring/ Terminations
 Enclosures

15. Infrared heat scans
of transformers when feeding the same
non-linear, computer load.

16. Benefits:
•Reduces the K-Factor Ratio of the loads.
•Saves energy.
•Prevents distribution system apparatus from overheating.
•Saves money.
•Balances phase currents and voltages on primary.
•Reduces voltage distortion.
•Increases system capacity and reliability.
•Reduces apparatus vibration and noise.
•Prevents electronic circuit breaker malfunctions.
•Provides a healthier environment for the loads.

17. .
MARKETS FOR HMT:
1 .EDUCATIONAL FACILITIESSchools and colleges have laboratories that contain
an ever-increasing number of
electronic devices which give rise to Harmonics. In
educational institutes HMTs
can be installed.
2. COMMERCIAL FACILITIESIn commercial office-buildings, customer service
call-centers, insurance companies, government offices,
presence of computers, printers and copying machines
create an environment that is full of Harmonics.
Installing HMTs can prevent losses.
3 .RETAIL FACILITIESElectronics and appliance stores as well as plaza
and malls and grocery stores typically make use
of electronic devices. HMTs can be used in these
places to avoid harmonics.

18. 4 .MEDICAL FACILITIESThese are the ideal locations for HMTs. Most modern diagnostic and analysis
equipments are electronic. Excessive harmonics may cause personal records or
medical test data to be corrupted or destroyed.
5.GAMNG INDUSTRYHMTs can be beneficial in
casinos, racetracks and offtrack-gaming parlors.

19. HMTs are a cost effective means of treating harmful
harmonics .
Reducing harmonic content in electrical systems can
result in a more reliable electrical system ,
lower maintenance cost ,less equipment malfunction
and lower cooling capacity.
In short , taking HARM out of HARMONICS
was never this easy .