ug power quality (ee2028) ppt

K.RAMAKRISHNAN COLLEGE OF TECHNOLOGY

DEPARTMENT OF EEE

EE2028– POWER QUALITY

FINAL EEE – 8TH SEM

Prepared By, Verified By,M.D.Udayakumar M.E., A.Nazar Ali M.E., (Ph.D)

AP / EEE HOD / EEE

EE2028 - Power Quality / Final EEE - 8th Sem

1

SYLLABUS

Unit I Introduction to Power Quality Unit II Voltage sags and interruptions

Unit III Over voltages Unit IV HarmonicsUnit V Power quality monitoring


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UNIT - I Introduction To Power Quality

CONTENTS:• Definition• Various Terms and Definitions• Description and types• CBEMA curve


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ENERGY• ENERGY CAN NEITHER BE CREATED NOR BE

DESTROYED BUT IT CAN BE CONVERTED FROM ONE FORM TO ANOTHER FORM.

4EE2028 - Power Quality / Final

EEE - 8th Sem

ELECTRICAL ENERGY

• GENERATION OF ELECTRICAL

ENERGY IS NOTHING BUT THE

CONVERSION OF VARIOUS OTHER

FORMS OF ENERGY INTO AN

ELECTRICAL ENERGY.


EEE - 8th Sem

WIND POWER PLANT


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HYDRO POWER PLANT


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SOLAR POWER PLANT


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THERMAL POWER PLANT


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ELECTRICAL POWER SYSTEM

• FLOW OF ELECTRICAL POWER FROM THE GENERATING STATION TO THE CONSUMER

1. GENERATING STATION

2. TRANSMISSION

3. DISTRIBUTION


EEE - 8th Sem


EEE - 8th Sem

POWER QUALITY DEFINITION

“ Any Power Problem manifested in Voltage,

Current, (or) frequency deviations that results

in failure (or) mis-operation of customer

equipment ”.

It is related to hardware, software (or) control

system malfunctions.13


WHY WE ARE CONCERNED ABOUT POWER QUALITY ?

The Main reasons behind the growing concern about PQ are:

• North American industries lose Tens-of-Billions of Dollars

every year in downtime due to power quality problems.

(Electrical Business Magazine)

• Load non-linearities in rising and is expected to reach 50 to

70% in the year 2005 (Electric Power Research Institute)

[Computers, UPS, fax machines, printers, fluorescent lighting,

ASD, industrial rectifiers, DC drives, arc welders, etc).


EEE - 8th Sem

WHY WE ARE CONCERNED ABOUT POWER QUALITY ?

• Economic impacts on utilities, their customers, and suppliers of load equipment.

• Meeting Customer Expectations

• Customers :

1. Industrial

2. Domestic

3. Commercial


EEE - 8th Sem

POWER QUALITY ISSUE AND PROBLEMS

Power Quality issues can be roughly broken into a number of sub-categories:

Harmonics (sub, super and inter-harmonics); Voltage swells, sags, fluctuations, flicker, and

transients Voltage magnitude and frequency deviation,

voltage imbalance (3ph sys.) Hot grounding loops and ground potential rise

(GPR)–Safety & Fire Hazards Monitoring and measurement. 16


BLOCK DIAGRAM GENERATION

TRANSMISSION & DISTRIBUTION

CUSTOMERS

INDUSTRIAL CUSTOMERS

RESIDENTIAL CUSTOMERS

COMMERCIAL CUSTOMERS


EEE - 8th Sem


EEE - 8th Sem

TRANSIENTS

• Used in the analysis of power system variations to denote an event that is undesirable and momentary in nature.

• Classified in to 2 categories(i) Impulsive Transient(ii) Oscillatory Transient


EEE - 8th Sem

TYPES OF TRANSIENTS

IMPULSIVE TRANSIENT• It is a sudden, non-power

frequency change in the steady state condition of voltage, current (or) both that is unidirectional in polarity.

• They are normally characterized by their rise and decay times, which can also be revealed by their spectral content.

OSCILLATORY TRANSIENT• It is a sudden, non-power

frequency change in the steady state condition of voltage, current or both, that includes both positive & negative polarity.

• Example :Capacitor Bank Energization.


EEE - 8th Sem


EEE - 8th Sem

OVERVOLTAGE• An overvoltage is an increase in the r.m.s. ac

voltage greater than 110 % at the power frequency for a duration longer than 1 min.

• It is a result of load switching.Eg : Switching OFF a Large load

Energizing a capacitor bank


EEE - 8th Sem

UNDERVOLTAGE

• An undervoltage is a decrease in the rms ac voltage to less than 90 % at the power frequency for a duration longer than 1 min.

Example : Load Switching Capacitor Bank Switching off


EEE - 8th Sem

INTERRUPTIONS

An interruption occurs when the supply voltage or load current decreases to less than 1p.u for a period of time not exceeding 1 min.

It can be the result of power system faults, equipment failures and control malfunctions.


EEE - 8th Sem

VOLTAGE SAG

• A sag is a decrease to between 0.1 and 0.9 p.u in r.m.s voltage or current at the power frequency for durations from 0.5 cycle to 1 min.


EEE - 8th Sem

VOLTAGE SAG


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VOLTAGE SWELL• A swell is defined as an increase 1.1 and 1.8

p.u in r.m.s voltage or current at the power frequency for durations from 0.5 cycle to 1 min.


EEE - 8th Sem

VOLTAGE IMBALANCE

• Also called Voltage Unbalance• Maximum deviation from the average of the

three phase voltages (or) currents.


EEE - 8th Sem

SYSTEM MODEL

Converter Type Arc Type Dynamic Cyclical Ripple Inrush Temporal Motorized on/off SMPS ASD Saturation Type

NonlinearLoad

NLL

R s L sV s V L

YF(s)

on/off orPWM

Load Bus

ElectricUtility

Transformer

System+Transformer+FeederElectric

Equivalent(Plant) Load

Switched/ModulatedPower Filter or Static

Capacitor Compensator

i s

ControlSignals

SmartController

*V s

Ps

SMPFDifferent

Topologies

Nonlinear Load (NLL)

* Smart-controllers arebased on specified control

objectives

eight designs(Dr. A.M. Sharaf) YF (TAF, C-Type, HPDF, Special Topology)


EEE - 8th Sem

TOTAL HARMONIC DISTORTION

• The ratio of the root mean square of the harmonic content to the r.m.s value of the fundamental quantity expressed as a percent of the fundamental.


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TOTAL HARMONIC DISTORTION


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WAVEFORM DISTORTION

• Steady-state deviation from an ideal sine wave of power frequency principally characterized by the spectral content of the deviation.

• 5 types of waveform distortion1. DC offset2. Harmonics3. Inter-Harmonics4. Notching5. Noise


EEE - 8th Sem

WAVEFORM DISTORTION TYPES


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ITI CURVE• ITI Curve ---- Information Technology

Industry Council Curve

• A set of curves published by ITI representing the withstand capabilities of computers connected to power systems in terms of magnitude and duration of the voltage disturbance.


EEE - 8th Sem

CBEMA CURVE

• CBEMA ---- Computer Business Equipment Manufacturers Association.

• A set of curves representing the withstand capabilities of computers in terms of the magnitude and duration of the voltage disturbance.

• Standard for measuring the performance of all types of equipment and power systems.


EEE - 8th Sem

CBEMA CURVE


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EEE - 8th Sem

ug power quality (ee2028) ppt

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