Project final year

1. Submitted To:
DR. IMRAN KHAN
H.O.D & Associate Professor
EE Department
Submitted By:
OM PRAKASH
B.Tech, VI sem
1705320903

2. • Abstract
• Introduction
• Definition of Power Quality (PQ)
• Importance of PQ
• Problems related to PQ
• Cost of PQ problems
• Solutions of PQ problems
• Conclusion
• References

3. In this seminar, the importance of good Power Quality (PQ) and its
main problems are presented with their associated causes and
consequences. The economic impacts associated with PQ are
characterized. Finally, some solutions to mitigate the PQ problems
are presented.

4. • Power Quality (PQ) related issues are of most concern
nowadays.
• Due to non-linearity
voltage waveforms.
of loads there is a disturbance in
• These loads
drives, PLCs etc.
are electronic equipments, adjustable speed

5. • Money factor also comes in play with power quality.
• When a disturbance occurs, huge financial losses may
happen, with the consequent loss of productivity and
competitiveness.
• The most critical areas are the continuous
process industries and the information technology services.

6. • Any deviation from a perfect sinusoidal waveform that can
result in failure or mis-operation of customer equipment
• Quality of the Current and voltage provided to the customers
-Providing customers with a clean sinusoidal waveforms at
Hz without sags or spikes.
50
-Providing power to allow sensitive electronic equipment operate
reliably.

7. • Proliferation of highly sensitive computerized equipment places
more stringent demands on PQ
-Semiconductor industry
-Computers and computer-related businesses
-Variable-speed drives or robots
-Programmable logic controllers
• Electronic equipment results in more PQ problems

8. • Deregulation of power industry creates more competitive
market
• Impact
-One cycle interruption makes a silicon device worthless
-Five minutes shut down of a chip fabrication plant causes delay
from a day to a week
- One second of power outage makes ecommerce sites lose
millions of dollars worth of business

9. Voltage sags
Major causes: faults, starting of large loads, and brown-out
recovery
Major consequences: shorts, accelerated aging, loss of data or
stability, process interrupt, etc.

10. Capacitor switching transients
Major causes: a power factor correction method
Major consequences: insulation breakdown or spark over,
semiconductor device damage, shorts, accelerated aging, loss of
data or stability

11. Harmonics
Major causes: power electronic equipment, arcing, transformer
saturation
Major consequences: equipment overheating, high voltage/current,
protective device operations

12. Lightning transients
Major causes: lightning strikes
Major consequences:
insulation breakdown or spark
over, semiconductor device
damage, shorts, accelerated
aging, loss of data or stability

13. High impedance faults
(One of the-most difficult power system protection
problems)
Major causes: fallen conductors, trees (fail to establish a
permanent return path)
Major consequences: fire, threats to personal safety High
Impedance Fault (RMS)

14. Noise
Description: Superimposing of high frequency signals on the
waveform of the power-system frequency.
Causes: Electromagnetic interferences provoked by Hertzian
waves such as microwaves, television diffusion,
and radiation due to welding machines, arc furnaces, and
electronic equipment
Consequences: Disturbances on sensitive electronic equipment,
usually not destructive. May cause data loss
and data processing errors.

15. The costs related to a PQ disturbance can be divided in:
• Direct cost
•Indirect Cost
• Non- material inconvenience

16. The mitigation of PQ problems may take place at different
levels
Transmission Distribution
Distribution
resources
Power
quality
interface
End-use
devices
Power Quality
Events
Assured grid
adequacy
Develop
advanced
distributed
resources
Develop
codes and
standards
Develop
enhanced
interface
devices
Make end-
use devices
less sensitive

17. • Many PQ problems have origin in the transmission or distribution
grid.
• Proper transmission and distribution grid, with adequate planning
and maintenance, is essential to minimize the occurrence of PQ
problems.

18. • Use of distributed energy resources (DER) has increased
substantially due of their potential to provide increased
reliability.
• Includes distributed generation and energy storage systems.
• Energy storage systems, also known as restoring
technologies,
• It is used to provide the electric loads with ride-through
capability in poor PQ environment.

19. Fig – Restoring technologies principle
Fig – Working principle of an energy storage
system.

20. • Electrochemical battery
• Flywheels
• Super capacitors
•Superconducting Magnetic Energy Storage (SMES)

21. • It is an electromechanical device that couples a rotating
electric machine (motor/generator) with a rotating mass to
store energy for short durations.
•Traditional flywheel rotors are constructed of steel and have
speed of few thousand rpm whereas advance ones are made up
of carbon fiber and have speed of 40,000 to 60,000 rpm
•They provide power during a period between power supply
failure and the start of a back up generator (diesel)

22. Fig – A Flywheel

23. • Ultra capacitors are DC energy sources
•must be interfaced to the electric grid
with a static power conditioner
• provides power during short duration
interruptions or voltage sags.
• medium size capacitors are available
commercially, large size capacitors are
still in development. Capacity is 50 to
60 J/g
Fig. 9 – Electric double layer
super capacitor

25. •Dynamic Voltage Restorer
•Transient Voltage Surge suppressors (TVSS)
•Constant Voltage Transformers
•Noise Filters
•Isolation Transformers
•Static VAR Compensators
•Harmonic Filters

27. • Designing the equipment to be less sensitive to disturbances is
usually the most cost effective measure to prevent PQ problems.
• Adding a capacitor with a larger capacity to power supplies,
using cables with larger neutral conductors,
transformers and adjusting under voltage relays,
de-rating
are measures that could be taken by manufacturers to reduce the
sensitivity of equipment to PQ problems

28. The availability of electric power with high quality is
crucial for the running of the modern society. To avoid the
huge losses related to PQ problems, the most demanding
consumers must take action to prevent the problems.
Among the various measures, selection of less sensitive
equipment can play an important role. When even the most
robust equipment is affected, then other measures must be
taken, such as installation of restoring technologies,
distributed generation or an interface device to prevent PQ
problems.

29. • A. de Almeida, L. Moreira. J. Delgado ISR “Power Quality Problems and
New Solutions”–Department of Electrical and Computer
University of Coimbra, Pólo II, 3030-290, Coimbra (Portugal)
Engineering,
• P.V.Chopade Member IEEE, V, A. Bugade LMISTE, D.G.Bharadwaj. “ A
step towards securing energy for the future. Ensuring Power Quality and
Reliability”. National Conference @ IIT Roorkee
• Dr. Kurt Schipman, Dr. François Delincé “The importance of good
Power Quality”, ABB Power Quality Products, Belgium
• Surya Santoso,” Power Quality Requirements for Reliability: Towards
`Perfect’ Power Quality”, University of Texas at Austin