POWER FACTOR IN ELECTRICAL ENERGY MANAGEMENT

Prepared by:Pratistha Senapaty0811013076Section-AElectrical Engg.

INTRODUCTION

1. Power factor is the percentage of electricity that is being used to do useful work

2. power factor= active power/apparent power3. 0<P.F.<1 & Dimensionless4. Apparent power(S) has two components:

Productive power(P) Reactive power(Q)

UNDERSTANDING OF POWER FACTOR

The conventional definition is only valid when considering IDEAL sinusoidal signals for both current and voltage waveforms.WHICH IS ONLY APPLICABLE IN CASE OF LINEAR CIRCUIT.

Instantaneous & average power calculated from ac voltage & current with unity power factor &0 power factor

(Instantaneous and average power calculated from ac Voltage & current with a lagging power factor)1.Power factors are usually stated as leading or lagging to show the sign of the phase angle.2.Poor power factors are always avoided , because the lower power factors come up with higher the apparent power associated with it.

more system losses More kva demand Require larger wire Require other equipments like transformers ,

protective relays Poor efficiency of power system equipments Wastage of available power

DISADVANTAGES OF LOW POWER FACTOR

EQUIPMENTS CREATING POOR POWER FACTOR

Lighting Incandescent Lamps

Fluorescent Lamps

Mercury Vapor Lamps

Distribution Transformer

Induction Motors

Synchronous Motors

BENEFITS OF POWER FACTOR CORRECTION

Benefit 1 - Reduce Utility Power Bills

Benefit 2 - Increase System Capacity

Benefit 3 - Improve System Operating Characteristics (Reduce Line Losses)

POWER FACTOR CORRECTION

Power factor correction can be made in two ways:•Reduce the amount of reactive energy •Compensate artificially for the consumption of reactive energy with power factor capacitor

Two type of equipment are available for power factor correction:

•Rotary Equipment: Phase advancers, synchronous motors and synchronous condensers

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.

1-reactive power control relay2-network connection points3-slow blow fuses4-inrush limiting contactors5-capacitors(delta connection)6-transformer suitable voltage Transformation to suit control Power.

AUTOMATIC POWER FACTOR CORRECTION UNIT

AUTOMATIC SWITCHING OF CAPACITORS

POWER FACTOR IN NON LINEAR CIRCUIT

A non linear power system is the system where current is interrupted by switching action , the current contains frequency components that

are multiples of power system frequency.

A non linear load on a power system is typically a rectifier or some kind of arc discharge device like welding

machine or arc furnace etc. Power factor=(distortion power factor)(cos ⱷ) DPF=1/(1+THD^2)^0.5THD=total harmonic distortion of load current

Harmonics & Their EffectsHARMONICS: Signals of different frequency other than other than FundamentalsSOURCES:>Static power converters>rectifiers>inverters> arc and laddle furnacesthyristor controlled reactorsEFFECTS:>increased line losses>reduced efficiency of rotating machine>overstressing of capacitor>cable insulation failure>errors in metering equipments

POWER FACTOR CORRECTION IN NON LINEAR LOAD

First harmonics are eliminated by using filters or capacitor bankThen we go for either passive PFC or active PFC

Passive PFC:>requires larger inductor > here nonlinearity is eliminated using capacitor bank. >less efficient in comparison to active PFCActive PFC : >controls the amount of power that flows into the load to get P.F. nearly equal to 1 >more efficient.

CONCLUSION

Lastly after the completion of my project, I conclude that improvement of power factor is necessary in both consumer and supplier point of view. In some industries penalty is charged due to maintenance of low power factor. In some industries where power consumed by the load is low, high ratings of equipments are required. SVC Technologies and Synchronous Generator are used for the improvement of power factor.