fluke lpqi 2007 1. fluke lpqi 2007 2 fluke corporation corporate headquarters near seattle, wa, usa...

Fluke LPQI 2007 1

Fluke LPQI 2007 2

Fluke Corporation

Corporate Headquartersnear Seattle, WA, USA

European HeadquartersEindhoven, the Netherlands

Fluke LPQI 2007 3

Fluke Corporation

• Founded in basement of John Fluke’s home in Springdale, Connecticut, USA in 1948

• 2,400 employees worldwide

• Offices in 21 countries around the world

• Distributed in more than 100 countries

• Manufacturing facilities in Everett (USA), the Netherlands, the U.K. and China

Fluke PDM seminar Module 1 4

Measurements for Power Quality maintenance

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Industry trends

1) Growing concern for personal safety- complexity of today’s systems, bring over voltage risks

- international & national regulations (& guidance)

2) Increased attention on power related issues- deregulation of power distribution

- Increasing loads on power systems

3) Shift from reactive maintenance to preventive maintenance

– More work by fewer people

– Decreasing maintenance budget

– More complex equipment

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•Network Test•Scope Meters•Loop Cal.•Clamp Meter•DMM•Simple Testers

•PQ Analyzers•IR Temperature•Insulation testers

• 20 years ago…

– The primary goal of maintenance was loss prevention and the fundamental requirement was to provide the basic need at minimum cost.

• Today…

– Companies are researching all possible means to extend the productive life

Tool use by application*

Scheduled

TR

EN

D

Reactive

Preventive

Predictive

•Thermal Imaging•Ultrasonic testing•Vibration Analyzers •Recorders/Loggers•Motor/Circuit Test•Oil Testers

History of Maintenance Practices

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ReactiveMaintenance

Repair it when it fails

PreventiveMaintenance

Maintenance at regular intervals

PredictiveMaintenance

Problem detected before predicted failure.Maintenance planned ahead

Break-down

Time

Cost

Time

Cost

Time

Cost

Types of Maintenance

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Power Quality

• Effects of bad power quality are not immediately obvious

• Bad power quality can come from anywhere

• Consequences could be severe (production loss)

• Power quality problems are a root cause:– Malfunction

– Shutdown

– Excessive energy cost

– Decreased lifetime of equipment


Example

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Example

• This manufacturer is the third biggest power consumer of the local energy supplier. They produce fiber materials for sports equipment.

• A new heating system was installed on a key process

• During a routine check with a thermographic camera it was discovered there had been an increase in temperature of the neutral conductor.

• Check with a current clamp revealed 20A Phase currents & 40A Neutral current

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Example

• A power quality logger was used to gather the needed data.

• Connection was only possible on the distribution board connection, fused with 250A, not at the heater due to safety reasons.

• This makes analysis a bit more complex since the heater represents a small part of the total load

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Results

Question: Why does the neutral carry 60A and not only 6A which would be the difference between currents in L1, L2 and L3?

Current trend

Neutral current

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Results 2• Conclusion; there is a

third harmonic present in the neutral

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ConclusionFurther analysis showed that:

• The reason for the neutral conductor overload clearly is the heating installation, which generates high triplen harmonics

• More unbalances present so further more measurements would be very helpful.

What was the cause?• Regulators built into the heating system require harmonic filters which

were not installed

10A fund

35A 3rd

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Conclusion

• Thermal survey gives early warning of a problem

• Addition of new equipment can introduce problems which are not obvious or visible

• Performing system check “before” and “after” can prevent future failures

• “Balanced” loads still can have harmonic content running in the neutral


Measurement of Electrical Systems

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Measurement

1. Safety

2. Power Quality Measurement The effect of distortion on simple test tools Measurement of Harmonics Measurement Specifications Typical measurements

3. Power Quality Measurement Equipment Basic Measurements Test equipment types

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Measurement

1. Safety



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Safety of Measurement

• Example– DMM fitted with low energy fuse used incorrectly on

a high energy circuit

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Implemented in 1998All instruments have to be tested by an independent test house (2004)

Each instrument must be marked with an Overvoltage Category ( CAT I, II, III, IV )

As well as a voltage level (300, 600, 1000 Volts)

EN61010 LV Directive

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Category Rating

• CAT IV - Electricity meters and primary connection

• CAT III - Permanent connection to the fixed installation.

• CAT II - Appliances, portable tools etc.

• CAT I - Protected electronic circuits.

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Voltage Phase-Zero CAT I CAT II CAT III CAT IV

300 1500 2500 4000

600 2500 4000 6000 8000

1000 4000 6000 8000

Source Impedance 30 Ω 12 Ω 2 Ω 2 Ω

Voltage Phase-Zero CAT I CAT II CAT III CAT IV

300 1500 2500 4000

600 2500 4000 6000 8000

1000 4000 6000 8000

Source Impedance 30 Ω 12 Ω 2 Ω 2 Ω

Voltage Rating per Category Test Impulse Rating

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IEC 1010 / EN61010

• Regulations are not an option

• Second edition EN61010 ( 2004 ) requires independent testing

• Remember Test leads are CAT rated ...

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Available from Fluke

• Free Safety DVD

• Not sales focused

• Information on EN61010

• Interview with an arc blast survivor

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Measurement Seminar

1. Safety



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=

HarmonicsDistorted waveforms

-3

-2

-1

0

1

2

3

0 1 2 3 4 5 6t [msec]

sin(x)+0.8*sin(3*x+3.6)+0.5*sin(5*x+0.6)+0.22*sin(7*x+3.8)

Harmonic frequencies combine with the fundamental sine

wave to form non-sinusoidal (distorted) waveforms.

-1

-0.8

-0.6

-0.4

-0.2

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4 5 6t [msec]

sin(x)0.8*sin(3*x+3.6)0.5*sin(5*x+0.6)

0.22*sin(7*x+3.8)


Effect of distortion on test tools

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Measurement Methods• Both Clamp Meter’s are calibrated and functioning correctly

59.2 59.2 A ACA AC 40.5 40.5 A ACA AC

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• How does a measurement device measure the effective value of a waveform ?

• Two Methods - Averaging & True RMS

MeasurementSinewave

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• Effective (RMS) value = 1.11 X Average value.

Averaging Measurement

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Non-linear Loads Switching Power Supply

VoltsVolts

AmpsAmps

• What happens to the measurement device if the waveform is distorted by non-linear loads ?

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• Effective (RMS) value = 1.85 x Average value.

• An averaging measurement device (1.11 x) would read up to 40 % too low.

AVGRMS

Measurement Distorted Waveform

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Nuisance tripping at 60A ?

59.2 59.2 A ACA AC 40.5 40.5 A ACA AC

True RMS MeasurementTrue RMS Measurement Averaging MeasurementAveraging Measurement

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•A True RMS meter calculates the effective heating value of the distorted waveform

•This will include all harmonics

True RMS MeasurementTrue RMS / Harmonics

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• Peak value = 1.414 X RMS value.

• 1.414 = Crest Factor.

Crest Factor

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• Peak value = 2.9 X RMS Value.

• 2.9 = Crest Factor.

RMS

Peak

Crest FactorDistorted Waveform

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• Professional Multimeters usually rated at CF <3

• High Quality units rated at CF of 6

• Power Quality Analyzer CF >11

C.F. = 1.43 C.F. = 2.39 C.F. = 4.68

Crest FactorDistorted Waveforms

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Power Measurement

Screen Shots from a Fluke 43 Single Phase and a Fluke 434 Three Phase Screen Shots from a Fluke 43 Single Phase and a Fluke 434 Three Phase analyser analyser

Two Power Factors Two Power Factors

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Power Measurement

• System with no Harmonic content

True Power (W)

Reactive power (kVAr)

Cos φ (dpf) = true power (fundamental)

Apparent power (kVA)

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Power Measurement

• System with Harmonic content

True Power (W)

Reactive power (kVAr)

Reactive power(Harmonic component)

Cos φ (dpf) : true power/Reactive power (fundamental)PF: true power/reactive power (incl harmonics)

Apparent power including harmonics (kVA)

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Power Measurement

Screen Shots from a Fluke 43 Single Phase and a Fluke 434 Three Phase Screen Shots from a Fluke 43 Single Phase and a Fluke 434 Three Phase analyser analyser

Two Power Factors !Two Power Factors !

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Measurement where Harmonics are present

1. Always use True RMS

2. Check the crest factor rating

3. When measuring power be aware of PF vs Cos φ/(DPF)

C.F. = 1.43 C.F. = 2.39 C.F. = 4.68


2) Measurement of Harmonics

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EN50160 HarmonicsUpper limits for individual harmonic voltages at the supply terminals in % of nominal voltage. 95% of 10-minute average Vrms over 1 week must be below limits

Odd harmonics Even Harmonics

Not multiples of 3 Multiples of 3

Orderh

Relative voltage Orderh

Relative voltage Orderh

Relative voltage

5 6 % 3 5 % 2 2 %

7 5 % 9 1.5 % 4 1 %

11 3.5 % 15 0.5 % 6…24 0.5 %

13 3 % 21 0.5 %

17 2 %

19 1.5 %

23 1.5 %

25 1.5 %

VIRTUALLY ALL HARMONIC PROBLEMS ARE GENERATED VIRTUALLY ALL HARMONIC PROBLEMS ARE GENERATED “IN HOUSE”“IN HOUSE”

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IEC 61000-4-30 specificationTest Equipment

Class A Class B

Measurement Interval Accuracy

Power frequency Hz 10 sec ± 10mHz Manufacturer to indicate

Magnitude supply voltage Vrms 10 cycles ± 0.1% Manufacturer to indicate

Flicker (IEC 61000-4-15) Plt 2 hr ± 5% Manufacturer to indicate

Voltage dips, swells and interruptions, rapid voltage changes

½ cycle Vrms 10 ms ± 0.2% ½ cycle Vrms

Unbalance (method of symmetrical components)

Vrms fundamental 10 cycles ± 0.15% (uncert.)

Manufacturer to indicate

Harmonics (IEC 61000-4-7) THD, Harm V, A, Inter harmonics

10 cycles ± 1-5% Manufacturer to indicate

Transients (not specified) V peak 50 μ sec (200KS/s)

Mains signaling Inter harmonic 10 cycles ± 1-5% Manufacturer to indicate

Flagging Dip, swells, interruptions might create unreliable readings of Hz, Vrms, Unbalance and Harm.

Therefore Must be re flagged (dirty) to avoid miss interpretation

Not specified

Time synchronization External clock; GPS

1 period Manufacturer to indicate

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Harmonic Measurement

• For troubleshooting– Check the harmonics present

– Check for the levels of the harmonics

– Look for recognizable patterns

50 Hz 100 Hz 150 Hz 200 Hz

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Harmonic Measurement – PC Load

V, A, Hz MeasurementV, A, Hz Measurement Harmonic MeasurementHarmonic Measurement 3rd Harmonic Content3rd Harmonic Content

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Harmonic Measurement

Twelve pulse bridge - harmonic current

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Harmonic number

%

Six pulse bridge - harmonic current

0

5

10

15

20

25

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Harmonic number

%

PC / IT LoadPC / IT Load

6 Pulse Bridge6 Pulse Bridge 12 Pulse Bridge12 Pulse Bridge

Elec. Fluorescent Lighting Ballast Elec. Fluorescent Lighting Ballast

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Measurement Seminar

1. Safety



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Types of Measurement Tools

1. Power Quality Troubleshooting / Survey tools1. Devices designed as a measurement tool

2. Simple to use / Immediate measurements

3. Troubleshooting / Survey tool / some logging

2. Power Quality “Logging”– Devices designed for long term monitoring

– Record every parameter for detailed analysis

– Predictive Maintenance

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Power Quality Troubleshooting & Surveys

• Measurements

1. Volts Amps & Frequency

2. Power

3. Harmonics

4. Dips & Swells

5. Transients

6. Unbalance

7. Flicker

8. Inrush

9. Temperature

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1) Volts, Amps & Frequency• Using a Power Quality

Analyser

• View all of the main parameters at point of connection

• Graphical as well as numeric display can help highlight potential problems

ScopeScope

VectorVector

TrendTrend

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2) Power Measurement

• Typical power measurement information

• Shows the sides of the triangle

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3) Three Phase Harmonic Measurement

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4) Transient Measurement

• Cause….. interference

• Difficult to capture– Triggering of ‘scopes difficult…width, timing, peak value ?

• Modern power quality analyzers purpose built for the job

• Envelope trigger

• Accurate real time stamping is essential

240240VV

+X%+X%

- X%- X%

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5) Dips and Swells

• Recording of upstream and downstream sags can indicate loads causing problems

Upstream Sag Downstream Sag

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6) Unbalance

• The phase diagram gives a quick indication of phase relationships and balance

• In this example voltage unbalance is very small, but current unbalance is nearly 19%.

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7) Flicker Measurements

• A reading greater than 1 means that most people will perceive flicker in an incandescent bulb

• Measurement– Pst (1 min): Short-term flicker over 1

minute

– Pst: Short-term flicker over 10 minutes

– Plt: Long-term flicker over 2 hours

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8) Inrush

• Inrush Current Measurement– Momentary peak of current

during switch on.

– Current clamps can capture peak reading

– Analyzers can give time measurement

Screen Shot of a PQA showing start-up Screen Shot of a PQA showing start-up current generated by a cooling systemcurrent generated by a cooling system

Three Phase Inrush MeasurementThree Phase Inrush Measurement

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9) Temperature

•Many power quality problems initially result in an increase in temperature of components, connectors, cables and machinery

• Infra red non contact measurement is the ideal way to locate this type of problem

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Why infrared non-contact measurement?

1) Measurement from distance•Dangerous to contact (Electrical)•Difficult to reach •Moving objects

2) Measurement without contact•Very hot objects •Where contact would damage, contaminate or change temperature (Food & Chemical)

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Example Substations

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Substations

Both qualitative and quantitative inspections are Required to determine a fault

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Electrical connections

The connections on this evaporator pumpread over 50 degrees hotter on phase 3

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• The temperature readouts show that connection on the centre phase of this main lighting disconnect are hot, suggesting an unbalanced load

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Electrical unbalance or overload?

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Electrical unbalance or overload?

• Where is the increased resistance? On the left or on the right contact?

• A hot spot is not necessarily a faulty connection!


Fluke Power Quality

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Single Phase Troubleshooting

Fluke 345 Power Clamp Fluke 43B Analyzer

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Three Phase Troubleshooting

Fluke 435 Power Quality Troubleshooter

Fluke 1735 Power Logger

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Power Quality Logging

Fluke 1740 Series Power Quality Logger

Fluke 1760 Power Quality Logger

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Thermal Imaging

FlukeTi20 Thermal Imaging Camera

FlukeTi40 & Ti50 Advanced Camera’s

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More information • Fluke Power Quality Data available in the exhibition

area

• DVD’s– Thermal Imaging Application DVD– Safety DVD – EN61010– Power Quality Measurement DVD

• Fluke Website – www.fluke.co.uk

• Short term requirement ?

fluke lpqi 2007 1. fluke lpqi 2007 2 fluke corporation corporate headquarters near seattle, wa, usa...

Documents

fluke lpqi

neutral slide

netherlands slide

power systems

power quality logger

power distribution

fluke pdm seminar module

total load slide