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Power Factor & Need For Improvement

Power factor is a measure of how efficiently electricity is being used. A lower power factor means more reactive power is being used instead of productive power. This causes higher utility costs and requires larger equipment. Power factor can be improved by adding capacitors to offset reactive power from inductive loads like motors. Benefits include reduced power bills, increased system capacity, improved voltage regulation, and lower line losses. Common sources of low power factor are lighting, motors, and transformers. Power factor correction is achieved through parallel capacitor banks that make the load look more resistive. This improves the power factor and lowers operating costs.

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111 views16 pages

Power Factor & Need For Improvement

Power factor is a measure of how efficiently electricity is being used. A lower power factor means more reactive power is being used instead of productive power. This causes higher utility costs and requires larger equipment. Power factor can be improved by adding capacitors to offset reactive power from inductive loads like motors. Benefits include reduced power bills, increased system capacity, improved voltage regulation, and lower line losses. Common sources of low power factor are lighting, motors, and transformers. Power factor correction is achieved through parallel capacitor banks that make the load look more resistive. This improves the power factor and lowers operating costs.

Uploaded by

pakistan-
Copyright
© Attribution Non-Commercial (BY-NC)
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PPT, PDF, TXT or read online on Scribd
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POWER FACTOR & NEED FOR

IMPROVEMENT

by
Engineer Haji Mumtaz
Power Factor Basics
1. Power factor is the percentage of electricity that is being used to
do useful work
2. power factor= active power/apparent power
3. Apparent power has two components:
 Productive power
 Reactive power
 Any industrial process using electric motors (to drive
pumps, fans, conveyors, refrigeration plant etc.)
introduces inefficiencies into the electricity supply
network by drawing additional currents, called "inductive
reactive currents".
Resistive Loads====> Real
Power ( kW )

Voltage & Current are in phase


P = VI
Inductive / Capactive Loads
=====> Reactive Power ( kVAR )

Current Lags Voltage and Vice Versa P = VI

Reactive
Power
Real Power, Reactive
Power , Apparent Power
Power Factor
Power Factor is the ratio of Real Power to Total Power
Lassi Analogy

Power Factor = kW
kVA kVA
R
Pf= kW
kW+kVAR
kVA
= Lassi
Lassi + Foam kW
DISADVANTAGES OF LOW
POWER FACTOR

 Indirect costs of low power factor


 Direct costs of low power factor
 Loss in distribution capacity
i. Larger Investment
ii. Transformers
iii. Large size conductors
BENEFITS OF POWER
FACTOR CORRECTION

 Benefit 1 - Reduce Utility Power Bills

 Benefit 2 - Increase System Capacity

 Benefit 3 - Improve System Operating Characteristics (Gain


Voltage)

 Benefit 4 - Improve System Operating Characteristics (Reduce Line


Losses)
EQUIPMENTS CREATING
POOR POWER FACTOR

 Lighting Incandescent Lamps


 Fluorescent Lamps
 Mercury Vapor Lamps
 Distribution Transformer
 Induction Motors
 Synchronous Motors
Power Factor Correction

• Power factor correction is achieved by the


addition of capacitors in parallel with the
connected motor circuits and can be
applied at the starter, or applied at the
switchboard or distribution panel.
 Our Goal is to achieve as near and similar
as possible the power factor resembling a
Resistive Load, near to 1 , or unity power
factor
Parallel Capacitor Banks
 Supplied Voltage – 240 Volts Single phase.
 Motor input – 10 KW
 Power Factor – 0.65



Current (I1) = Power (kW)__ = 10000__ = 64.1 Amp.
 Volts (V) * PF 240*0.65

 If the power factor of the motor is increased to 0.9 the current
 drawn by the motor shall be –

 Current (I2) = Power (kW)__ = 10000__ = 46.3 Amp.
 Volts (V) * PF 240*0.9

 Thus, as the power factor decreases the current required for the same
 value of active, or useful, power increases. The result is that the sizes of the
 equipment, like the switchgear, cables, transformers, etc., will have to be
 increased to cater the higher current in the circuit. All this adds to cost
AUTOMATIC SWITCHING OF
CAPACITORS
Questions & Answers 

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