Precision is measurable

The use of renewable energies reveal specific

requirements for electricity meters

Precision is measurable

General Meter testing

reasons for incorrect operation

Precision is measurablePTB Topic of ZMP 2011: 2 kHz - 150 kHz

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Precision is measurable

Meter testing / Reasons for incorrect operation

• How currents outside of the 50 Hz frequency range arise?

• Why are some electricity meters get disturbed by a frequency from 2 kHz?

• What type of meter is to be selected for which electricity consumers?

• How can ensure the correct function of the meter?

• How can you check the meter installation, easy, safty and fast?

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Precision is measurable

How currents outside of the 50 Hz frequency range arise?

Example: switched-mode power supply

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Circuit diagram of a switched-mode power supply

Voltage- and Currentcurve

Precision is measurable

How currents outside of the 50 Hz frequency range arise?

Example: switched-mode power supply

Fourier Transformation

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Current profile of a switched-mode power supply 80% 150-Hz-Anteile50% 250-Hz-Anteile22% 350-Hz-Anteile

-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)

Fourier Transformation for I Netz:

Precision is measurable

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household industry

photovoltaic plants photovoltaic plants

block heating station (Dachs Stirling) wind engine

Energy saving lamp Temperaturgeregelte Heizungen und Öfen

Computer, Audio- and Video devices welding machine

Dimmer elevator

Induction cooker Dynamic reactive-power compensation systems

freezer electronic frequency converter

How currents outside of the 50 Hz frequency range arise?

Examples

Precision is measurable

Why are some electricity meters get disturbed by a frequency from 2 kHz?

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40. harmonic =

40 x 50 Hz = 2 kHz

EN 61000-2-2 und EN 50160

The frequency range from 2-9 kHz is in Europ curenntly not regulatet in the EMV Norm.

Precision is measurable

Jan. 2012 9

What type of meter is to be selected for which electricity consumers?

Production: Installation of highly accurate meters and measuring transformers in power plants

Transmission: Transfer stations between different networks

Customers: Installation of meters and measuring transformers on the consumer’s premises

Production CustomersTransmission

Precision is measurableWhat type of meter is to be selected for which electricity consumers?

The solar electricity-magazine PHOTON reported in the November 2010 edition already, that some electronic power meter are to slow …

… Some inverters are not compatible with electronic energy meters. Who is using the wrong combination of devices must be feared that his input meter shows too little income. The problem is known in professional circles for at least three years, some Operators even have blacklists....

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Frank GreizerSMA Solar Technology AG

(Bereichsleiter Technologieentwicklung)

… be seen from any point of any failure or fault of

SMA and see the buck at the meter manufacturers

…

Karsten PetersonItron Zähler& Systemtechnik GmbH (Vertriebsleiter Deutschland)

… by the inverter generates extra power and pollution would have to actually work to avoid these …

Typ Iskra MT171 shows up to 20% less

Precision is measurable

What type of meter is selected for electricity consumer?

The VDE-project team „ Measurement reliability and stability of electricity meters and accessories“ has conducted studies on this topic.

In the laboratory of the VDE Testing and Certification Institute, 12 electronic electricity meters has been tested. It has been determined error of over 70%. (graphic left)

In the following customers are high-frequencys expected :

•Solar inverter systems

•Wind turbines

•pumping stations

•commercial operation / metal working

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Precision is measurable

Type testing and standards norms EN 50470-X (for electronic electricity meters) will soon be expanded and standardized.

At customer site with high frequency system size it is possible to check the meter with the real system size on site with appropriate measuring instruments

More possible disturbances: DC, DC voltage, stress peaksmodulated frequency changes( Flicker)overburden of Current- and Voltagetransformer

transport damage of the meterconnection erros during the installation of the meter

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How ensure the correct work of the meter?

Precision is measurable

On site test

• Collection of network variables

• Connection check

• Error measurement

• logging

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ZERA stands for innovation, flexibility and sustainability

Precision is measurable

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ZERA stands for innovation, flexibility and sustainability

Precision is measurable

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Thank you for your attention

Matthias Heinzen Sales Manager

ZERA GmbHHauptstrasse 392

D-53639 Koenigswinter

m.heinzen@zera.de