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NAME:- NITESH ARUN KAMBLI
TITLE:- AUTOMATIC POWER FACTOR
CORRECTOR.
CONTENTS
Power Factor: An Introduction
Types of PF Correction
• Static Capacitor
• Synchronous Condense
• PhaseAdvancer
Importance of power factor
Disadvantages of low power factor
Principle
Section ofAPFC
Advantages
Result
Conclusion
Introduction
It is also defined as the cosine of the
angle between the voltage and current
phases.
Power Factor (cos Ø) = Active Power
(kW) / Apparent Power (kVA).
The closer cos Ø is to unity, the less
reactive power is drawn from the
supply.
TYPES OF PFC
There are Three types of power factor correction
as follow.
• Static Capacitor
• Synchronous Condense
• PhaseAdvancer
The type of loads which doesn’t change Which is
always constant there we used Static Capacitor.
The load which is changed i.e. dynamic in nature
there we used synchronous condenser or phase
advancer.
IMPORTANT OF POWER
FACTOR
Lower Utility Charges
• Reducing Peak KW billing demand
• Eliminating the power factor penalty
Increased System Capacity and Reduced
System Losses in our Electrical System
• By adding capacitors (KVAR generators)
to the system, the power factor is improved
and the KW capacity of the system is
increased.
DISADVANTAGES OF LOW PF
Higher current is required by the equipment, due to which the
economic cost of the equipment is increased.
Large Line Losses (Copper Losses)
• We know that Line Losses is directly proportional to the squire
of Current “I2” Power Loss = I2xR i.e., the larger the current,
the greater the line losses.
Large kVArating and Size of Electrical Equipment
• As we know that almost all Electrical Machinery rated in kVA
• Therefore, The Lower the Power factor, the larger the kVA
rating of Machines also, the larger the kVArating of Machines.
• The larger the Size of Machines and The Larger the size of
Machines, The Larger the Cost of machines.
Greater Conductor Size and Cost
• In case of low power factor, current will be increased, thus, to
transmit this high current, we need the larger size of conductor.
PRINCIPLE
Automatic Power Factor detection and correction operates on the
principal of constantly monitoring the power factor of the system and to
initiate the required correction in case the power factor is less than the set
value of power factor.
The current and voltage signals are sampled by employing instrument
transformers connected in the circuit.
The sampled analog signals are converted to suitable digital signals by the
zero crossing detectors.
The ZCD signals are then added in order to obtain pulses which represent
the time difference between the zero crossing of the current and voltage
signals.
The time period obtained is used to calculate the power factor of the
circuit.
Now if the calculated power factor is less than the minimum power factor
limit set at about 0.96-0.98, then the microcontroller switches on the
require number of capacitors until the power factor is greater than or equal
to the set value.
ADVANTAGE
It’s an automatic system adjusting itself to control the power
factor above a desired value by a bank of capacitors switched
by means of contractors
Contractors are controlled by a regulator that measures PF in
the network
Depending upon the load PF the controller will adjust the PF
by switching the necessary no of capacitors from the bank
SECTION OFAPFC
Power supply:-
Basically this section provide supply to all circuit of
our system which perform different operation.
Sensing Section:-
This section sense current and voltage across the load
and then using this signal consider particular power
factor and signal send to control circuit.
Controlling Section:-
This section sense pf and switch capacitor across load
and improve pf accordingly.
ADVANTAGES
They have low losses.
They require little maintenance as there are no
rotating parts.
They can be easily installed as they are light and
require no foundation.
They can work under ordinary atmospheric
conditions.
INDUCTIVE LOAD:-
Before PFC:-
RESULT
 AFTER PFC:-
 RESISTIVE LOAD:-
CONCLUSION
• The Automatic Power Factor Detection and Correction provides an efficient
technique to improve the power factor of a power system by an economical
way. Static capacitors are invariably used for power factor improvement in
factories or distribution line.
• However, this system makes use of capacitors only when power factor is low
otherwise they are cut off from line. Thus, it not only improves the power
factor but also increases the life time of static capacitors.
• The power factor of any distribution line can also be improved easily by low
cost small rating capacitor. This system with static capacitor can improve the
power factor of any distribution line from load side.
• As, if this static capacitor will apply in the high voltage transmission line then
its rating will be unexpectedly large which will be uneconomical & inefficient.
So a variable speed synchronous condenser can be used in any high voltage
transmission line to improve power factor & the speed of synchronous
condenser can be controlled by microcontroller.
Thanks you