Power Quality is a combination of Voltage profile, Frequency profile, Harmonics contain and reliability of power supply. The Power Quality is defined as the degree to which the power supply approaches the ideal case of stable, uninterrupted, zero distortion and disturbance free supply.

1. Power Quality Improvement

2. INTRODUCTION OF POWER
QUALITY
 Power Quality is a combination of Voltage profile,
Frequency profile, Harmonics contain and reliability of
power supply.
 The Power Quality is defined as the degree to which
the power supply approaches the ideal case of stable,
uninterrupted, zero distortion and disturbance free supply.

3.  This presentation represents an overviews of electric
power quality with special emphasis on power quality
problems.
 The adverse impact on utility of customers and their
mitigation techniques.
 This presentation also deals with serious power quality
problems such as voltage distortion due to current
harmonics, flicker ,voltage sag and voltage surge..etc
 Power quality is related to deliver of “CLEAN”
electric power that compile with industry standards.

4. CAUSES OF POOR POWER
QUALITY
 Variation in voltage magnitude and frequency.
 Variation in magnitude can be due to sudden rise or fall of
load , outages, repetitive varying loading pattern in rolling
mills, power electronic converters, inverters, lightning..etc
 Variation in frequency can rise of out of system dynamics
or harmonics injection.

5. POWER QUALITY COVERS
1. Reliability :- continuous availability,
interruption/breakdown/outage free
2. Parameters:-
 Voltage- flicker, swell, sag/dip, unbalance
 Frequency- drop or rise
 Harmonics contains- SCR, converters, inverters etc.
 Transients

6. SOURCES OF POOR POWER
QUALITY
 Non linear loads
 Arcing loads
 Switching operation
 Reactive loads
 Atmospheric condition
 Unstable loads
 Neighboring unbalance system

7. TYPICAL POWER QUALITY
PROBLEMS
 Voltage Sags :- A reduction in RMS voltage or
current at the power frequency.

8. Voltage Surge:- voltage variation can be
positive (higher than normal) or negative (lower
than normal)

9.  Transients:- it manifest only as a short duration
change in voltage due to switching ON and OFF the
loads.
 Harmonics:- it is an integer multiple of fundamental
frequency in the sine wave of power supply or simply
distortion of waveforms.
 Lightning:- It produces very high currents, for a short
time interval, but enough to cause fires or to destroy
microcircuits.

10. IMPACT OF POOR POWER QUALITY
 The effect of poor power quality problems has serious implication on
the utilities and customers.
 Higher losses in transformers, cables .
 Neutral wire burning due to third harmonics generated by non linear
loads.
 Power factor capacitors may punctures.
 Energy meters will give faulty readings.
 Solid state protective relays may damaged .
 Speed drives may shut down.
 Motor will increase core and cu losses
 Non sinusoidal waveforms will reduce the efficiency of motors.
 Electronic computer may loss data due to voltage variation .
 Domestics TV and other equipments are affected by the poor quality.

11. SYMPTOMS OF POWER QUALITY
PROBLEM
 Electronic controlled system that stop unexpectedly
 Abnormal failure of electronic systems
 Transformer overheating
 Motor failing
 Power factor capacitors failing
 Test results will unreliable

12. TECHNIQUES TO MITIGATE
POWER QUALITY PROBLEMS
 Compensation techniques can be broadly classified into
two main categories:-
1. Passive techniques
2. Active techniques
 Passive techniques employ the following devices.
* Passive Shunt L-C Filters
* Power Factor Correction Capacitors
 Active techniques employ the following devices.
*PWM Active Filters.

13. SOME OTHER TECHNIQUES
 Segregate sensitive loads on separate branch
circuits , fed from a separate panel board , fed from
a separate feeders
 Use of harmonics rated circuit breakers, panel
board and transformers.
 Use surge and lightning protection.
 Oversize phase conductors to minimize voltage
drop.
 Choose material of superior quality.

14. CONCLUSION
The wide spread applications of non-linear power
electronics loads increases the poor power quality in the
electric systems. This presentation has focused broadly on
the utilities and customers in the power system. At the
same time, the sources of poor power quality and their
mitigations techniques has discussed in brief. The
effectives means of compensation through various
techniques have also been highlighted.

15. THANK YOU…!!!