Mikro PFCR Explanation

Power Factor RegulatorPower Factor RegulatorIndustri Teknologi Mikro Sdn. Bhd.

Electric LoadsElectric Loads

Resistive LoadResistive Load Power supplied is totally transformed into useful Power supplied is totally transformed into useful

workwork

Current = Active Current (ICurrent = Active Current (IAA))

Reactive LoadReactive Load Power supplied is Power supplied is NOTNOT transformed into useful transformed into useful

workwork

Inductive load and capacitive load Inductive load and capacitive load

Current = Reactive Current (ICurrent = Reactive Current (IRR))

VV--I Vector DiagramsI Vector Diagrams

Power Power Resistive LoadResistive Load

Power Power Inductive LoadInductive Load

Inductive + Resistive Inductive + Resistive

PowerPower

PowerPower

Active Power (P)Power actually consumed by the load

P = V IA (kW)

Reactive Power (Q)Necessary power but not transformable in useful energy

Q = V IR (kVAR)

Apparent Power (S)Total power that flows toward the load

S = V I (kVA)

Power Factor (PF)Power Factor (PF)

PF is a measurement of how effectively a PF is a measurement of how effectively a

system is converting electric power to system is converting electric power to

useful output power.useful output power.

PF always less than or equal to one (1).PF always less than or equal to one (1).

The lower the PF, the lower the efficiency.The lower the PF, the lower the efficiency.

Power Factor ReadingsPower Factor Readings

Displacement Power Factor (Displacement Power Factor (DPFDPF))CosCos -- Cosine of the phase angle (Cosine of the phase angle ()) between between

the fundamental frequency of voltage and the fundamental frequency of voltage and

current. Only phase shift between V & I.current. Only phase shift between V & I.

Total Power Factor (Total Power Factor (PFPF))True ratio of active power to apparent powerTrue ratio of active power to apparent power

Phase shift and harmonic distortionPhase shift and harmonic distortion

PF =Active Power (P)

Apparent Power (S)=

kW

kVA

Power TrianglePower Triangle

"Power triangle" without effect of "Power triangle" without effect of

harmonicsharmonics

Harmonic EffectHarmonic Effect

"Power triangle" with effect of harmonics"Power triangle" with effect of harmonics

Causes of Low Power FactorCauses of Low Power Factor

Most electrical systems have lagging power Most electrical systems have lagging power

factor due to inductive loads such as motor, factor due to inductive loads such as motor,

airair--conditioner, fluorescent lighting etc.conditioner, fluorescent lighting etc.

0.40 0.40 0.900.90Phase controlled rectifierPhase controlled rectifier

0.500.50Arc weldingArc welding

0.700.70Fluorescent lightingFluorescent lighting

0.70 0.70 0.800.80Induction motorInduction motor

Power factorPower factorLoadLoad

Typical PF of loads

Benefits of PF CorrectionBenefits of PF Correction

Reduced electricity billsReduced electricity bills

Gained in system capacityGained in system capacity

Reduced line lossesReduced line losses

Improved voltage conditionImproved voltage condition

PF Correction MethodsPF Correction Methods

Connect capacitors in parallel to the Connect capacitors in parallel to the

system.system.

Capacitor produces leading PF thus Capacitor produces leading PF thus

neutralize the lagging PF.neutralize the lagging PF.

If low PF due to harmonics is significant, If low PF due to harmonics is significant,

harmonic filter is required.harmonic filter is required.

Capacitor will Capacitor will NOTNOT help to improve low PF help to improve low PF

caused by harmonics.caused by harmonics.

PF Correction by CapacitorPF Correction by Capacitor

BeforeBefore AfterAfter

Calculate Required kVARCalculate Required kVAR

Table of Output Factor kTable of Output Factor k

0.480.480.260.260.160.16--------------0.900.90

0.750.750.520.520.420.420.270.270.130.13----------0.800.80

1.021.020.790.790.690.690.540.540.400.400.270.270.140.14------0.700.70

1.331.331.101.101.001.000.850.850.710.710.580.580.450.450.310.310.160.16--0.600.60

1.731.731.501.501.401.401.251.251.111.110.980.980.850.850.710.710.560.560.400.400.500.50

1.001.000.980.980.950.950.900.900.850.850.800.800.750.750.700.700.650.650.600.60(Cos(Cos11))

Desired Desired PF(CosPF(Cos 22))Original Original

PFPF

Power Factor Regulator (PFR)Power Factor Regulator (PFR)

What is PFR?What is PFR?

A device to monitor and maintain the A device to monitor and maintain the

required power factor of an electrical required power factor of an electrical

network.network.

Working principle of PFRWorking principle of PFR

PFR continuously measures the network's PFR continuously measures the network's

reactive power (reactive power (kVARkVAR) and then correct it by ) and then correct it by

switching in/out of the capacitor banks to switching in/out of the capacitor banks to

achieve the targeted power factor.achieve the targeted power factor.

Mikro's Power Factor Mikro's Power Factor

RegulatorRegulator

Model PFR60 Model PFR60 6 switching outputs6 switching outputs



Model PFR140 Model PFR140 14 switching outputs 14 switching outputs

Power Factor Measurement: Power Factor Measurement:

DPF or PF?DPF or PF?

CapacitorCapacitor banksbanks are only designed to are only designed to

compensate compensate the the reactive powerreactive power of the of the

fundamental frequency component.fundamental frequency component.

Capacitor Capacitor banks are not designed tobanks are not designed to

correct total power factor where harmonic correct total power factor where harmonic

currents are included.currents are included.

DPF DPF measurement method is measurement method is more more

suitable for power factor regulatsuitable for power factor regulator.or.

How to measure DPFHow to measure DPF

Zero crossing methodZero crossing method

MeasureMeasures the s the phase anglephase angle difference difference

between between the respective the respective zero crossing of the zero crossing of the

voltage & current waveforms.voltage & current waveforms.

Numerical Numerical mmethodethod

The phase angle is computed using The phase angle is computed using

mathematical methodmathematical method through the regularly through the regularly

sampled voltage and current waveforms.sampled voltage and current waveforms.

DPF Measurement (1)DPF Measurement (1)

DPF Measurement (2)DPF Measurement (2)

Features of Mikro's PFRFeatures of Mikro's PFR

DPF measurement by numerical method.DPF measurement by numerical method.

Accurate measurement even in the presence Accurate measurement even in the presence

of harmonics.of harmonics.

Capacitors improve DPF only.Capacitors improve DPF only.

Cause & Effect of HarmonicsCause & Effect of Harmonics

CausesCauses

NonNon--linear loads draw nonlinear loads draw non--sinusoidal sinusoidal

currents.currents.

e.g. Adjustablee.g. Adjustable--speed motor drive & speed motor drive &

energy saving lighting.energy saving lighting.

EffectsEffects

Overheating and dielectric breakdown of Overheating and dielectric breakdown of

capacitors.capacitors.

Excessive current caused by resonanceExcessive current caused by resonance

Increase losses.Increase losses.

Features of Mikro's PFR (2)Features of Mikro's PFR (2)

Total harmonics distortion (THD)Total harmonics distortion (THD)

measurement and alarm.measurement and alarm.

Able to measure current THD.Able to measure current THD.

Disconnect all capacitor banks in the Disconnect all capacitor banks in the

event of THD alarm to prevent damage event of THD alarm to prevent damage

of capacitors due to harmonics.of capacitors due to harmonics.


Intelligent automatic switching program.Intelligent automatic switching program.

Improve switching efficiency by reducing Improve switching efficiency by reducing

the number of switching operationthe number of switching operationss..

Able to measure Able to measure kvarkvar required and select required and select the the

most appropriate most appropriate switching switching stepsteps.s.

Evenly distribute usage of each capacitor Evenly distribute usage of each capacitor

bank.bank.

Switch in least used capacitorSwitch in least used capacitor

Switch out longest used capacitorSwitch out longest used capacitor

Features of Features of Mikro'sMikro's PFR (4)PFR (4)

Programmable switching sensitivity.Programmable switching sensitivity.

Optimized switching speed.Optimized switching speed.

Reaction time inversely proportional to the Reaction time inversely proportional to the

reactive powerreactive power required.required.


Alarm functionsAlarm functions

Under/over voltage alarm.Under/over voltage alarm.

Under/over load current alarm.Under/over load current alarm.

Under/over compensate alarm.Under/over compensate alarm.

THD alarm.THD alarm.

Light indicator for alarm.Light indicator for alarm.

Programmable last output Programmable last output step step as alarm as alarm

output contact.output contact.


Automatic Automatic current transformer (current transformer (CTCT)) polaritypolarity

Automatic correction of CT polarity when Automatic correction of CT polarity when

reversed.reversed.

Programmable rated stepProgrammable rated step

Enable flexible usage of capacitor with Enable flexible usage of capacitor with

different sizes.different sizes.


Programmable reProgrammable re--connection timeconnection time

Safety lockout time to prevent reSafety lockout time to prevent re--connection connection

of the same capacitor step before it is fully of the same capacitor step before it is fully

dischargeddischarged

Programming lockProgramming lock

To prevent inadvertent changes to the user To prevent inadvertent changes to the user

programmed parameters.programmed parameters.

Mikro PFCR Explanation

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