Mr Ramesh Bhatia [Compatibility Mode]

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Effective Power Quality Monitoring System

Ramesh Bhatia

enera anager(Corporate Sales)

Schneider Electric Conzerv India Pvt Ltd

123rd Sept

2008 `


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Power Quality - Expectations

From Utilities:> Stable Voltage

n s or e o age ave orm

From Customer:

> Maintainin Good Power Factor

>> Incentive for good PF

>> KVAH Billing

> Generate no armon cs>> No regulation yet

2 16-Sep-09 Copyright 1986-2005, ConZervProprietary & Confidential


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of poor quality

Industry resorting to power from DG sets forcritical operations due to frequent and

unscheduled interruptions, unstable voltage etc.

Poor PF results in higher T&D Losses. Harmonics result in damage to capacitors, other

equipment, overheating etc



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HARMONIC IS DEFINED AS A COMPONENT OF PERIODIC WAVE

THE FUNDAMENTAL FREQUENCY.

CURRENT HARMONIC

VOLTAGE HARMONICS



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HARMONIC COMPONENTS



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Harmonic Distortion Standards

No BIS known or available.

limits and these are termed as Users

.

Voltage distortion limits are termed as

.



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ISC/I1


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Bus Voltage at Individual Voltage THD

.

69>161 KV 1.5 2.5

>161 KV 1.0 1.5

916-Sep-09 Copyright 1986-2005, ConZerv Proprietary & Confidential


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Distortion Limits - Effects

Difficult to establish a correlation between distortionamplitude and harmful effects.

ect o vo tage stort ons on generat on o current

harmonics in a plant is also difficult to predict.

mitigation should be resorted to. Harmonics analysis

followed by monitoring is the only way.



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EFFECTS OF HARMONICS

POOR POWER FACTOR

UNEXPLAINABLE OVERHEATING OF TRANSFORMERS AND AUDIBLEHUM

SUDDEN INCREASE IN KVA DEMAND AND PENALISATION BY EB

FREQUENT FAILURE OF CAPACITORS & CONTACTORS

NUISANCE TRIPPING OF DRIVES

HEATING OF CABLES AND MOTOR WINDINGS

DEGRADATION OF SYSTEM EFFICIENCY

ENERGY LOSSES

SAFETY RISKS



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SUMMARY OF PROBLEMS DUE TOHARMONICS

Blinking of Incandescent Lights Transformer Saturation

Capacitor Failure Harmonic Resonance

Circuit Breakers Tripping Inductive Heating and Overload

Computer Malfunction or Lockup Voltage Distortion

Conductor Failure Inductive Heating

Electronic Equipment Shutting down Voltage Distortion

Fuses Blowing for No Apparent Reason Inductive Heating and Overload

Motor Failures (overheating) Voltage Drop

eu ra on uc or an ermna a ures ve rp en urren s Electromagnetic Load Failures Inductive Heating



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SUMMARY OF PROBLEMS DUE TO

HARMONICS CONT'D

Overheatin of Metal Enclosures Inductive Heatin

Power Interference on Voice Communication

Harmonic Noise Transformer Failures Inductive Heating



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Effects of Harmonics

Excess harmonics in network can lead to:- Excess energy consumption

Poor capacity utilisation of network

Damages to components like capacitors, D G sets,.

Nuisance tripping of circuits leading to production loss

And man more associated roblems



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Schneider Electric A Global Company

, crore revenue n

countries

>200 factories around the world


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Schneider Electric in India

5,500 employees

9 manufacturing sites, 4 distribution centers around

the country, 2 R&D centers in Bangalore

400 authorized partners (Distributors, System

Integrators and Panel Builders)

One Regional Project & Engineering Centre


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and Conzerv

Energy Efficiency


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* Energy Efficiency


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FACTORS EFFECTING POWER FACTOR



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Relevance of K Factor( Source : Xitron Technologies)

Harmonic currents cause overheating intransformers and other equipment.

K Factor defines the heating effect of harmonics.

K Factor 1.0 indicates linear load with noharmonics.

Transformer supplying non linear loads may

require de-rating.



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Relevance of K Factor( Source : Xitron Technologies)

RMS load current maybe higher thanindicated b KVA load.

Increase in Eddy currents due to harmonics

.

Either oversize de-rated transformer or

required



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Crest Factor( Source: Environmental Potentials)

Crest factor is ratio of peak voltage to rms value ina voltage waveform.

For sinusoidal waveform Crest factor is 2

Lower crest factor indicates flat topped waveformwhereas crest factor higher than 1.41 indicates

spiky shape.

Crest factor has relevance in the harmonicscontent of a waveform.



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o a armon c s or on( Source:Environmental Potentials)

Total harmonic distortion is Ih/If for currentwhere Ih is effective value of all harmonics and If is effective value

of fundamental

For sinusoidal voltages or currents THD iszero.



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n us r a ower ac or ( Source: EnvironmentalPotentials)



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n us r a ower ac or ( Source: EnvironmentalPotentials)

When sinusoidal voltage is applied across variablespeed drives or thyristor controlled equipment the

resultant current waveform could take the shape as

shown in the previous slide. Spikes would imply high frequency content of

current.

y re uc ng e s arpness o sp es w use ofilters power factor can be improved.



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Factor( Source: Environmental Potentials)

Power factor is cos , where is the phasedifference between current and voltage. Power iscalculated from VI Cos.

When distorted waveshapes are present,expression for power becomes more complex and

meaning of PF has to be enlarged. It is then called

.



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Factor ( Source: Environmental Potentials)



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E ect o Harmon cs on Power actor( Source: Environmental Potentials)

Waveshape in the previous slide consists of fundamentalwith 5th ,7th and higher harmonics of amplitude

, . .

respectively.

Waveshape depends not only on the harmonic content butalso on their respective phase differences.

For this current waveform, power will also be a complex

calculation based on displacementpower ac or.



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Power Factor

EB Billing Unity

= tan - tan

Or use the capacitor selection chart



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e evance o ower ac or n ense s

Good Power Factor when operating

Gensets reduces T&D losses= 2

flowing thru cables and R is cable

Genset engine should not be overloaded.If

.

loading should not exceed 800 KW.



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Location of capacitors

Main distribution boards (Unity)

u str ut on oar s o.

Load ends (0.85)



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Benefits of PF Improvement

Avail rebates from SEB

e uce eat oss o networ

Voltage improvement

Reduced maximum demand charges



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Solution for Power Factor

Power Quality Audit can indicate sources orloads which have low PF.

Installation of PFI Panel consisting of PF

Controller with Capacitors, Contactors etc Install Intelligent Power Factor Controller if

capacitors with manual control already exist.

If capacitors are inadequate for achieving requiredPF, then capacitors will have to be added.



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ower ac or mprovemen ane Compact modular stand

alone unit Comprises of capacitors,

Contactors, isolating switch,

HRC fuses Power factorController

Models from 35kVAr to

200kVAr

37 16-Sep-09 Copyright 1986-2005, ConZerv

Proprietary & Confidential


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Monitoring




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Instrumentation for Measurement



EMS SYSTEM


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EMS SYSTEM

CONZERVeLAN

LAN NETWORK

HUBDATA

CONVERTOR



EM 6000 SeriesRS 485-RS232

CONVERTOR

DATA

CONVERTOR

ETHERNET

CONVERTOR

EM 3000 Series


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Benefits of Monitoring

PF variations in distribution

Harmonics level through THD

re ct ve a ntenance sc e u e o

equipments based on run hours

Manpower reduction


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42 16-Sep-09 Copyright 1986-2005, ConZervProprietary & Confidential42 16-Sep-09 Copyright 1986-2005, ConZerv Proprietary & Confidential

H EIP k


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How EIP works.

Broadban

d

User EMS PC Conzerv

ServerOnline Analysis of

Plant Data



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DSL CONNECTION

Online Data

ISP(Internet Service Provider)

GSM /CDMAMODEM

CONZERV HO

GSM/CDMA

TOWER

MODEMEMS PC

Fig: Schematic diagram EIP (Way to Save)Fig: Schematic diagram EIP (Way to Save)



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SOLUTION FOR HARMONICS

Detailed harmonic analysis

Filters

- ct ve ass ve ters

- Tuned / Detuned Filters



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SOLUTION FOR HARMONICS

HARMONIC FILTER SYSTEM

HARMONIC FILTER SYSTEM IS A COMBINATION OFCAPACITOR BANKS WITH SERIES REACTOR

TUNED FOR A PREDOMINANT FREQUENCY

PROVIDES LOW IMPEDANCE PATH FOR THE HARMONIC

CURRENTS BELOW HARMONIC FREQUENCY, IT IS CAPACITIVE AND

INJ ECTS REACTIVE POWER TO THE NETWORK AND ABOVEHARMONIC FREQUENCY IT IS INDUCTIVE



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Monitoring Harmonics

Necessity for monitoring arises when some untoward

incidents in power distribution occur.

n t a y a u e ge armon c ana ys s s ou e carr e

out to establish the extent of the problem. In this analysis

amplitude of individual harmonic at all loads ofsignificance should be measured and solution

implemented.

,

at such loads to verify and establish that no deterioration

takes place.



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Factor

Capacitors used for PF improvement mayet dama ed and even blow u due to

harmonics as capacitors offer low

im edance to hi h fre uenc currents. PF Capacitors resonating with inductive

due to heavy voltage build up.



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MEASUREMENTS



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True RMS vs Average Sensing

Meters can be of two types Average sensing or true rms.

There is significant difference in measurement when

.

True rms is .707 of peak value in perfect sinusoid or

equivalent DC level which produces same heating effect.Av sensing for perfect sinusoid is the same.

When waveform is other than sinusoid av sensing value

.



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Measurements


P l d l


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Power quality measuring and control


NETWORK ANALYZER


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NETWORK ANALYZER


NETWORK ANALIZER:


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, ,



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Detect



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TRANSFORMER 21

(Individual Harmonic Level)



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TRANSFORMER 20 (V ,I, KW GRAPHS)



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TRANSFORMER 20 (PF GRAPHS)



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TRANSFORMER 20 (WAVEFORM DISTORTION)



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TRANSFORMER 20 (Individual Harmonic Level)



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