This document discusses power factor and methods for power factor correction. It defines power factor as the ratio of active power to apparent power. Low power factor causes disadvantages like increased equipment costs and copper losses. Methods for power factor correction include static VAR compensators, fixed and switched capacitors, synchronous condensers, and static synchronous compensators. A case study examines the improvements in power factor, active power, reactive power, apparent power and current before and after installing a capacitor bank at an industrial unit.
2. OUTLINE
DEFINITION
CAUSE OF LOW POWER FACTOR
DISADVATNAGES OF LOW POWER FACTOR
METHODS OF POWER FACTOR
CORRECTIONS
CASE – STUDY
REFERECES
3. DEFINITION
Power factor is the measure of how effectively
your electrical equipment converts electric power-
KVAs (supplied by your power utility) into useful
power output-KWs.
In technical terms, it is the ratio of Active Power
(KW) to the Apparent Power (KVA) of an
electrical installation.
POWER FACTOR =Active power/Apparent
power.
Its values lies between 0 -1.
4. POWER FACTOR TRIANGLE
• KW is Working Power (also called
Actual Power or Active Power or Real
Power). It is the power that actually
powers the equipment and performs
useful work.
• KVA is Apparent Power. It is the
“vectorial summation” of KVAR and
KW.
• KVAR is Reactive Power. It is the
power that magnetic equipment
(transformer, motor and relay) needs to
produce the magnetizing flux.
5. CAUSES OF LOW POWER
FACTOR
Induction generators (wind mill generators)
High intensity discharge (HID) light.
Transformers-due to Magnetising currents.
Distorted current waveform-rectifier variable speed
drive, switched mode power supply, discharge
lighting or other electronic load.
High HARMONIC contents – electronic converters.
Induction furnaces.
Induction motors (60 % load is IM in homes and
industries).
6. DISADVANTAGES OF LOW POWER
FACTOR
Reactive power (KVAR) required by inductive loads
increases the amount of apparent power (KVA) in
distribution system.
This increase in reactive and apparent power results in
a larger angle measured between KW and KVA.
CURRENT =POWER/(VOLTAGE X POWER
FACTOR).
Due to higher current the economic cost of the
equipment is increased.
High current gives rise to high copper losses in the
system cause reduction in the efficiency of system.
Higher current produced a large voltage drop in the
apparatus results in the poor voltage regulation.
7. NEED OF POWER FACTOR
IMPROVEMENT
Reduction in COPPER LOSSES, hence size of
conductor.
EFFICIENCY will improve.
Cooling in equipments improves.
LOWER the Utility bill.
Voltage regulation improves.
Increase System Capacity.
Less total plant KVA for the same KW working
power.
8. POWER FACTOR
CORRECTION
POWER FACTOR CORRECTION
METHODS Static VAR Compensator(SVC)
Fixed Capacitors( Shunt and series)
Switch Capacitors
Synchronous Condensers
Static Synchronous Compensator(STATCOM)
Modulated power filter capacitor compensator
9. STATIC VAR COMPENSATOR
(SVC)
The Static VAR Compensator (SVC) is a shunt
device of the Flexible AC Transmission Systems
(FACTS) family using power electronics to control
power flow.
Improves transient stability on power grids .
It regulates voltage at its terminals by controlling the
amount of reactive power injected into or absorbed
from the power system. When system voltage is low,
the SVC generates reactive power (SVC capacitive).
When system voltage is high, it absorbs reactive
power (SVC inductive).
11. FIXED CAPACITORS
where the load does not change or where the
capacitor is switched with the load, such as the load
side of a Ideally suited for power factor correction
in applications motor contactor.
It is suitable for locations using induction motors,
like food processing plants, or where small multiple
loads require reactive power compensation.
Each Fixed Capacitor Bank is designed for high
reliability and long life. These products are
designed for applications that do not contain
harmonic generating .
13. SWITCHED CAPACITOR
It is suited for power factor correction in
applications where plant loading is constantly
changing, resulting in the need for varying
amounts of reactive power.
An advanced microprocessor-based reactive
power controller measures plant power factor via
a single remote current transformer
15. SHUNT COMPENSATION
The device that is connected in parallel
with the transmission line is called the
shunt compensator.
A shunt compensator is always
connected in the middle of the
transmission line. It can be provided by
either a current source, voltage source
or a capacitor.
An ideal shunt compensator provides
the reactive power to the system.
16. SYNCHRONOUS CONDENSER
Synchronous condenser is a
salient pole synchronous
motor .
Can be operate as lagging
and leading load as well.
Synchronous condenser
stabilizes power system
voltage by supplying
reactive power to the power
system .
Use for power factor
correction. It is more
economical than capacitors
18. CASE STUDY
A Unit at IAL SANGRUR supplied with power from a
utility through 1600 KVA ,11/.433kv transformer.
The maximum demand of reactive power of this unit is
1250 KVA at power factor 0.75 . A 300 KVAR capacitor
bank was installed at this unit to raise power factor.
In this case study, the measurement of power factor
(PF),
active power (P), reactive power(Q),apparent power(S),
and current (I) were illustrated for 12 hours(6:00-
18:00hours) in a day time before and after operating the
Capacitor Bank in the unit.
22. CONCLUSION
The average power factor was improved by 21% as it
was 0.75 before and becoming 0.95 after PFC.
The average loading on the transformer released by
26% as it was 372 KVA before PFC and became 296
KVA after PFC.
Losses of the cable was reduced by 36% as average
current was before 497 Amps and 395 Amp after PFC.
The capacitor compensated by 61% of the consumed
reactive power as the average was 245 KVAR before
PFC and became 96 KVAR after PFC.
23. REFERENCES
WIKIPEDIA .COM
IEEE JOURNAL ON POWER FACTOR.
V.K.MEHTA –INTRODUCTION TO POWER
SYSTEM.
IAL SANGRUR (GENERATING UNIT).
