POWER QUALITY IMPROVEMENT BY POWER QUALITY IMPROVEMENT BY UNIFIED POWER QUALITY CONDITIONERUNIFIED POWER QUALITY CONDITIONER

INTROUCTIONINTROUCTION

• VOLTAGE QUALITY

voltage quality is concerned with deviations of the voltage from the ideal.

the ideal voltage is a single frequency sine wave of constant frequency

and constant magnitude.

• CURRENT QUALITY current quality is concerned with deviations of the current from

the ideal. the ideal current is again a single frequency sine wave of

constant . frequency and constant magnitude.

POWER QUALITY

it is the combination of voltage quality and current quality.

Power quality is the concept of powering and grounding sensitive in a

matter that is suitable to the operation of that equipment.

POWER QUALITY ISSUESPOWER QUALITY ISSUES

SYSTEM SYSTEM » » LOADLOAD

• Voltage sag/swellVoltage sag/swell

• Voltage unbalanceVoltage unbalance

• Voltage distortionVoltage distortion

• Voltage interruptionVoltage interruption

• Voltage oscillationsVoltage oscillations

LOAD LOAD » SYSTEM» SYSTEM

• Current harmonicsCurrent harmonics

• Reactive currentReactive current

• Current un balanceCurrent un balance

• Voltage notchingVoltage notching

• Voltage flickerVoltage flicker

Harmonics Harmonics are associated with steady-state waveform distortion

of currents and voltagesHarmonics are components that make up a waveform where

each component has a is normally applied to waveform components that have frequencies other than the fundamental

frequency. For a 50 Hz or 60Hz system the fundamental frequency is 50HZ or 60Hz. A waveform that contains any components other than the fundamental frequency is non-

sinusoidal and considered to be distorted.  

Nonlinear loads draw currents that are non-sinusoidal and thus create voltage drops in distribution conductors that are non-sinusoidal. Typical nonlinear loads include rectifiers, variable

speed drives, and any other loads based on solid-state conversion. Transformers and reactors may also become nonlinear elements in a power system during overvoltage

conditions. Harmonics create many concerns for utilities and customers alike. Typical phenomena include neutral circuit overloading in three phase circuits, motor and transformer

overheating, metering inaccuracies and control system malfunctions.

OBJECTIVESOBJECTIVES

Classification of active power filtersClassification of active power filters

based on converter typebased on converter type

based on topologybased on topology

base on number of phasesbase on number of phases

Objective of UPQCObjective of UPQC

OUTLINEOUTLINE

LITERATURE SURVEYLITERATURE SURVEY

IEEE 519 Voltage Limits

GENERAL THEORY OF ACTIVE POWER FILTERSGENERAL THEORY OF ACTIVE POWER FILTERS

IEEE 519 Voltage LimitsIEEE 519 Voltage Limits

Bus Voltage MinimumIndividualHarmonic

Components (%)

MaximumTHD (%)

69 kV and below 3 5

115 kV to 161 kV

1.5 2.5

Above 161 kV 1 1.5

IEEE 519 Current IEEE 519 Current LimitsLimits

SCR=Isc/Il h<11 11 to 17 17 to 23 23 to 35 35<h THD

<20 4.0 2.0 1.5 0.6 0.3 5.0

20 - 50 7.0 3.5 2.5 1.0 0.5 8.0

50 -100 10.0 4.5 4.0 1.5 0.7 12.0

100 - 1000 12.0 5.5 5.0 2.0 1.0 15.0

>1000 15.0 7.0 6.0 2.5 1.4 20.0

Classification of ACTIVE POWER FILTERSClassification of ACTIVE POWER FILTERS

based on converter typebased on converter type

• Current Source Inverter (CSI) Current Source Inverter (CSI) Active Power Filter Active Power Filter

• Voltage Source Inverter (VSI) Voltage Source Inverter (VSI) Active Power Filter Active Power Filter

Voltage Source

Fig 3.2 Voltage fed type AF

FIG.1 FIG.1 Current fed type AF Fig .2 Voltage fed type AFCurrent fed type AF Fig .2 Voltage fed type AF

Current fed type AF

Topology based ClassificationTopology based Classification

• Shunt type AF Shunt type AF

• Series type AFSeries type AF

• UPQCUPQC

Fig 3.3 Shunt-type AF

Fig.3 Shunt-type AF Fig .4 Series-type AF Fig.3 Shunt-type AF Fig .4 Series-type AF

Fig .6 Unified Power Quality ConditionerFig .6 Unified Power Quality Conditioner

Supply-System-Based ClassificationSupply-System-Based Classification

• 1)1)    Two-Wire AF’s:Two-Wire AF’s:

• 2)   2)   Three-Wire AF’s:Three-Wire AF’s:

• 3) Four-Wire AF’s:3) Four-Wire AF’s:Three-Wire AF’s 1)      Three-Wire AF’s:

Compensated Variable Based ClassificationCompensated Variable Based Classification

• (1) Harmonic Compensation(1) Harmonic Compensation

• (2) Multiple Compensation(2) Multiple Compensation

· · Harmonic currents with Reactive power compensation.Harmonic currents with Reactive power compensation.

· Harmonic voltages with Reactive power compensation.· Harmonic voltages with Reactive power compensation.

· Harmonic currents and voltages.· Harmonic currents and voltages.

· Harmonic currents and voltages with reactive-power · Harmonic currents and voltages with reactive-power compensationcompensation..

Voltage Type Vs Current Type APF’sVoltage Type Vs Current Type APF’s

Operation of Three Phase Active Power FiltersOperation of Three Phase Active Power Filters

Fig.7 Configuration of the three phase, three wire Active filtering system.Fig.7 Configuration of the three phase, three wire Active filtering system.

Fig 3.8 Control block of Sample and Hold circuit's harmonic reference template

Fig 3.8 Control block of Sample and Hold circuit's harmonic reference template

Fig 3.8 Control block of Sample and Hold circuit's harmonic reference template

Sample and Hold circuit’s method for harmonic reference templateSample and Hold circuit’s method for harmonic reference template

Fig 3.9 Method used to capture IFig 3.9 Method used to capture IPP..

Topology based Classification Topology based Classification 2)

COMPARISION OF VARIOUS CONTROL COMPARISION OF VARIOUS CONTROL STRATAGIES FOR APF’S AND DESIGN STRATAGIES FOR APF’S AND DESIGN CHARACTERISTICS OF THE PWM CHARACTERISTICS OF THE PWM MODULATORMODULATOR

Fig 3.9 Method used to capture IP.Fig 3.9 Method used to capture IP.

IntroductionIntroduction

Various modulation methods for single phase Various modulation methods for single phase

systemsystem

• Error Saw tooth ControlError Saw tooth Control

• Hysteresis controlHysteresis control

• Sampled error controlSampled error control

Error Saw tooth ControlError Saw tooth Control

Fig 4.1 Block diagram of error saw tooth control.Fig 4.1 Block diagram of error saw tooth control.

Hysteresis controlHysteresis control

Fig 4.2 Hysteresis control operationFig 4.2 Hysteresis control operation

Various modulation methods for Various modulation methods for three-phase systemthree-phase system

Periodic Integral Control Periodic Integral Control

Three Phase Hysteresis ControlThree Phase Hysteresis Control

Three Phase Sampled Error Three Phase Sampled Error ControlControl

Three Phase Hysteresis Control Three Phase Hysteresis Control