Smart meter testing

VDE|FNN concerning the reliability of electronic meters

VDE | FNN has taken account of known disturbing effects in the specifications for basic meters, which can lead to incorrect measurements. So far, no mis-measurements have been reported on devices that have been tested according to FNN recommendations for the reliability assessment.

Christian Lütkemeier

Against the background of current media reports on faulty measurements of digital electricity meters, the Forum Network Technology / Network Operation in the VDE (FNN):

The media reports are based on a study of the University of Twente Enschede in the Netherlands. VDE | FNN develops technical specifications for interoperable and exchangeable devices as components for intelligent measuring systems ("smart meters") for Germany. The reliability of the meters and auxiliary equipment has always been the focus since the end user and metering companies are reliant on reliable electricity meters and additional devices at all times.

It is known that various disturbing effects such as the increasing spread of energy saving lamps or LEDs as well as the decentralized supply of renewable energies can lead to faulty measurements. The reasons for this are high-frequency currents in the frequency range from 2 kHz to 150 kHz, which, e.g. a solar inverter can produce when built-in filters are not sufficiently dimensioned.

Against this background, VDE | FNN carried out extensive investigations in 2010 together with the VDE Testing and Certification Institute. The results and conclusions have been incorporated into a FNN article ("Guidance on the reliability and measurement resistance of electricity meters and accessories"). This document describes extended requirements for test methods that allow a systematic assessment of the reliability of electricity meters. Specifically, methods are described which prove that the meters also measure correctly in the critical range. Since 2011, this guide has facilitated the development of devices that are resistant to interference during operation.

VDE | FNN has defined a basic meter for the upcoming rollout of modern measuring devices and intelligent measuring systems in Germany and has made reference to the above-mentioned guideline. So far no mis-measurements on devices are known, which were developed according to FNN-specifications. Meters which were tested according to the FNN guideline for the reliability test of 2011 have demonstrated their strength against the mentioned disturbances. Development and testing of the devices is the responsibility of the manufacturers.

The current study from the Netherlands is now being examined for new findings and disturbance phenomena. Furthermore, the transferability to Germany and the German electricity market is examined. VDE | FNN is closely aligned with the Federal Network Agency and the National Metrology Institute of Germany.

If new findings are gained, for example, on hitherto unknown disturbance phenomena, they are incorporated into the development of the basic meter. The specifications and guidelines are part of the activities of VDE | FNN to make innovative technologies faster and more accessible to everyday life.

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