power quality

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TECHNICAL SEMINAR ON POWER QUALITY MONITORING:

TECHNICAL SEMINAR ON POWER QUALITY MONITORING Presented By: SUSREE ADITI PATHY REGDNO:0801204063 SAGAR SUDHA DASH REGDNO:0801204039 UNDER THE GUIDANCE OF Mr. S.R. DASH

CONTENT:

CONTENT WHAT IS POWER QUALITY PQ PROBLEMS DESCRIPTION OF PQ PROBLEMS WAVEFORMS:PQ DEFINITIONS SOURCES OF PQ PROBLEMS PQ PROLEMS & POSSIBLE CAUSES WHO GET AFFECTED HOW THEY AFFECT HOW TO MONITOR BENEFITS OF PQ MONITORING CONCLUSION REFERENCE

WHAT IS POWER QUALITY:

WHAT IS POWER QUALITY The term Power quality is used to describe the extent of variation of the voltage, current and frequency on the power system. The variation of voltage and current can either be in terms of magnitude or waveform shape/distortion . WHAT IS POWER QUALITY MONITORING The best way to detect and diagnose the problems in electrical power system is called Power quality monitoring

POWER QUALITY PROBLEMS:

POWER QUALITY PROBLEMS 1.Disturbance Voltage sag Voltage interruption Voltage swell Transient Voltage notch 2.Imbalance 3.Distortion 4.Voltage fluctuation 5.Voltage flickering

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1. DISTURBANCES A DISTURBANCE IS DEFINED AS THE TEMPORARY DEVIATION FROM THE STEADY STATE WAVEFORM. VOLTAGE SAG Reduction in voltage magnitude for a short period of time. VOLTAGE INTERRUPTION Voltage sag with 100% reduction in amplitude . DESCRIPTION

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VOLTAGE SWELL Increase in RMS voltage or current at the power frequency between 1.1 to 1.9 per unit for a duration of 8milisec to 1min . TRANSIENT Voltage disturbance shorter than sag/swell and are caused by sudden changes in power system . VOLTAGE NOTCH Periodic transient occuring within each cycle.

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2. IMBALANCE A SITUATION IN WHICH VOLTAGE,FREQUENCY AND PHASE ALL ARE DIFFERENT. 3. DISTORTION IT IS GENERALLY EXPRESSED IN TERMS OF HARMONICS WHICH ARE SINUSOIDAL VOLTAGES OR CURRENTS HAVING FREQUENCY THAT ARE INTEGER MULTIPLE OF THE FREQUENCY AT WHICH THE SUPPLY SYSTEM IS DESIGNED TO OPERATE.

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4. VOLTAGE FLUCTUATION THE RAPID CHANGE IN VOLTAGE MAGNITUDE IN THE ALLOWABLE LIMIT I.E ., 95% TO 105%. 5. VOLTAGE FLICKERING THE COLOUR OCCURING WHEN THE FREQUENCY OF VARIATION OF LIGHT FLUX LIES BETWEEN FEW HERTZ AND FUSION FREQUENCY.

PQ is a Business Problem:

PQ is a Business Problem Power Quality issues cause business problems such as: Lost productivity, idle people and equipment Lost orders, good will, customers and profits Lost transactions and orders not being processed Revenue and accounting problems Customer and/or management dissatisfaction Overtime required to make up for lost work time According to Electric Light and Power Magazine, 30 to 40 Percent of All Business Downtime Is Related to Power Quality Problems.

Why PQ is such a Big Problem?:

Why PQ is such a Big Problem? The sensitivity of today’s electronic equipment makes it susceptible to power disturbances For some devices, a momentary disturbance can cause scrambled data interrupted communications a frozen mouse system crashes and equipment failure

PQ Problems are Expensive:

PQ Problems are Expensive Berkeley Lab Study Estimates $80 Billion Annual Cost of Power Interruptions … Research News, Berkeley Lab, February 2, 2005 $50 billon per year in the USA is lost as a results of power quality breakdowns …. Bank of America Report A manufacturing company lost more than $3 million one day last summer in Silicon Valley when the “lights went out.” … New York Times January 2000 “A voltage sag in a paper mill can waste a whole day of production - $250,000 loss” … Business Week, June 17,, 1996 Half of all computer problems and one-third of all data loss can be traced back to the power line … Contingency Planning Research, LAN Times

Who is Affected?:

Who is Affected? High Cost Facilities Semiconductor plants Pharmaceuticals Data centers Medium Cost Facilities Automotive manufacturing Glass plants Plastics & Chemicals Textiles

PQ Definitions Revisited:

IEEE Categories Std 1159-1995 Short Duration Variations Typical Duration Instantaneous Sag 0.5 – 30 cycles Momentary Sag 30 cycles – 3 sec Temporary Sag 3 sec – 1 min PQ Definitions Revisited

PQ Definitions Revisited:

PQ Definitions Revisited IEEE Categories Std 1159-1995 Short Duration Variations Typical Duration Instantaneous Sag 0.5 – 30 cycles Momentary Sag 30 cycles – 3 sec. Temporary Sag 3 sec – 1 min. Instantaneous Swell 0.5 – 30 cycles Momentary Swell 30 cycles – 3 sec. Temporary Swell 3 sec – 1 min.

PQ Definitions Revisited:

PQ Definitions Revisited IEEE Categories Std 1159-1995 Short Duration Variations Typical Duration Instantaneous Sag 0.5 – 30 cycles Momentary Sag 30 cycles – 3 sec. Temporary Sag 3 sec – 1 min. Instantaneous Swell 0.5 – 30 cycles Momentary Swell 30 cycles – 3 sec. Temporary Swell 3 sec – 1 min. Momentary Interruptions 0.5 – 30 cycles Temporary Interruptions 30 cycles – 3 sec.

PQ Definitions Revisited:

PQ Definitions Revisited IEEE Categories Std 1159-1995 Long Duration Variations Typical Duration Sustained interruptions > 1 min Under voltages > 1 min Over voltages > 1 min

PQ Definitions Revisited:

PQ Definitions Revisited IEEE Categories Std 1159-1995 Long Duration Variations Typical Duration Sustained interruptions > 1 min Under voltages > 1 min Over voltages > 1 min Voltage imbalance Steady state Waveform Distortion

PQ Definitions Revisited:

PQ Definitions Revisited IEEE Categories Std 1159-1995 Long Duration Variations Typical Duration Sustained interruptions > 1 min Under voltages > 1 min Over voltages > 1 min Voltage imbalance Steady state Waveform Distortion DC offset Steady state Harmonics Steady state Inter harmonics Steady state For Electric Utilities Control of Voltage and Prevention of Outages is Power Quality

Sources of PQ Problems:

Sources of PQ Problems Utility Sources Lightning PF Correction Equipment Faults Switching Internal Sources Individual Loads –Lighting, Elevators, Coolers, HVAC Uninterruptible Power Supplies Variable Frequency Drives Battery Chargers Large Motors During Startup Electronic Dimming Systems Lighting Ballasts (esp. Electronic) Arc Welders, and Other Arc Devices Medical Equipment, e.g. MRIs and X-Ray Machines Office Equipment and Computers Wiring

PQ Problems and Possible Causes:

PQ Problems and Possible Causes Typical problems Disturbance Type Possible Causes Overheated neutral Intermittent lock-ups Frequency deviations Steady-state Shared neutrals Improper or inadequate wiring High source impedance SCR/Rectifiers and notching Harmonics

PQ Problems and Possible Causes:

PQ Problems and Possible Causes Typical problems Disturbance Type Possible Causes Overheated neutral Intermittent lock-ups Frequency deviations Steady-state Shared neutrals Improper or inadequate wiring High source impedance SCR/Rectifiers and notching Harmonics Interruption Garbled data Random increase in harmonics levels Utility faults Inrush currents Inadequate wiring

PQ Problems and Possible Causes:

PQ Problems and Possible Causes Typical problems Disturbance Type Possible Causes Overheated neutral Intermittent lock-ups Frequency deviations Steady-state Shared neutrals Improper or inadequate wiring High source impedance SCR/Rectifiers and notching Harmonics Interruption Garbled data Random increase in harmonics levels Utility faults Inrush currents Inadequate wiring Intermittent lock-ups Lights flicker Garbled data Sags/Swell Source voltage variations Inrush/surge currents Inadequate wiring

PQ Problems and Possible Causes:

PQ Problems and Possible Causes Typical problems Disturbance Type Possible Causes Overheated neutral Intermittent lock-ups Frequency deviations Steady-state Shared neutrals Improper or inadequate wiring High source impedance SCR/Rectifiers and notching Harmonics Interruption Garbled data Random increase in harmonics levels Utility faults Inrush currents Inadequate wiring Intermittent lock-ups Lights flicker Garbled data Sags/Swell Source voltage variations Inrush/surge currents Inadequate wiring Component failure Dielectric breakdown Lock-ups Garbled data Wavy CRTs Impulses EMI/RFI Lightning Load switching Capacitor switching Static discharge Hand-held radios Loose wiring/arcing

PQ Problems and Possible Causes:

Typical problems Disturbance Type Possible Causes Overheated neutral Intermittent lock-ups Frequency deviations Steady-state Shared neutrals Improper or inadequate wiring High source impedance SCR/Rectifiers and notching Harmonics Interruption Garbled data Random increase in harmonics levels Utility faults Inrush currents Inadequate wiring Intermittent lock-ups Lights flicker Garbled data Sags/Swell Source voltage variations Inrush/surge currents Inadequate wiring Component failure Dielectric breakdown Lock-ups Garbled data Wavy CRTs Impulses EMI/RFI Lightning Load switching Capacitor switching Static discharge Hand-held radios Loose wiring/arcing Overheated transformers and motors Voltage and current distortions Garbled data Lock-ups Harmonics Electronic loads SCR/rectifier PQ Problems and Possible Causes

Major PQ Problems:

Major PQ Problems Spikes, 7% Sags, 56% Outages, 6% Swells, 31% Sags (Dips) Associated with system faults Switching of heavy loads Starting of large motors Swells System fault conditions Switching on a large capacitor bank Switching off a large load

Cost of Voltage Sags:

Cost of Voltage Sags Textile Industry Plastics Industry Glass Industry Process Industry Semiconductors $1k $10k $100k $1M $10M Losses per Voltage Sag Event

HOW DO THEY AFFECT YOU:

HOW DO THEY AFFECT YOU Motors stall Computers crash Production is affected Equipment damaged Product spoilage ‘The lights go out’

HOW TO MONITOR :

HOW TO MONITOR POWER QUALITY PROBLEM SOLUTION VOLTAGE SAG UPS,DVR,CVT VOLTAGE INTERRUPTION UPS VOLTAGE SWELL UPS,POWER CONDITIONER TRANSIENT SVC VOLTAGE NOTCH SNUBBER CKT IMBALANCE PROTECTION SCHEME DISTORTION SERIES & SHUNT ACTIVE FILTER VOLTAGE FLUCTUATION SVC VOLTAGE FLICKERING VOLTAGE UNBALANCED RELAY

BENEFITS OF POWER QUALITY MONITORING:

BENEFITS OF POWER QUALITY MONITORING Direct Benefits / Technical Benefits – Energy Savings – Release of blocked capacity – Reduced temperature rise – Increased reliability / Life of equipment (e.g. Transformer, Motors, capacitors...) – Reduced mal-function of equipment (e.g. Drives, Relays,Meters ) Indirect / Regulatory Benefits – Penalty savings / Incentives (e.g. Demand charges, pf penalty) – Tax benefits – Compliance to standards & Regulations

CONCLUSION:

CONCLUSION DISTURBANCES PLACE ALL BUSINESSES AT RISK BOTH IN TERMS OF FINANCIAL LOSSES AND ENERGY EFFICIENCY SO THEY SHOULD BE TAKEN SERIOUSLY. POWER QUALITY MONITORING IS VERY ESSENTIAL TO GET AN UNINTERRUPTABLE AND EFFICIENT POWER SUPPLY.

REFERENCES :

REFERENCES • UNDERSTANDING POWER QUALITY PROBLEMS – VOLTAGE SAGS &INTERRUPTIONS, MATH H J BOLLEN, IEEE PRESS. • AN INTEGRATED APPROACH TO POWER QUALITY IMPROVEMENT, R VENKATESH & S R KANNAN, - ET POWER TECH 2001. • SOLUTIONS TO THE POWER QUALITY PROBLEM, PROF. RAY ARNOLD,IEE POWER ENGINEERING JOURNAL, APRIL 2001 • POWER QUALITY ISSUES A DISTRIBUTION COMPANY PERSPECTIVE,IEE POWER ENGINEERING JOURNAL, APRIL 2001 • MONITORING POWER FOR THE FUTURE, AFROZ K. KHAN, IEEPOWER ENGINEERING JOURNAL, APRIL 2001

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THANK YOU THANK YOU THANK YOU

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ANY QUERIES

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