17NRM02 MeterEMI: Electromagnetic Interference on Static Electricity Meters

• Forschungsstelle: METAS
• Projektnummer: F-5213.30101

Schlüsselwörter (Englisch)

Static Electricity Meters, Smart meters, Electromagnetic Interference (EMI), electrical energy, metering, billing, utilities, legal metrology, Measuring Instruments Directive (MID), type approval

Kurzbeschreibung (Englisch)

Smart electricity meters are currently widely being deployed by utilities across the Europe. Recent studies have reported serious errors in some meters when exposed to interference of the type caused by some home appliances. This project will determine the extent of this problem by measuring the interference at a representative selection of meter installations and electrical products. Advanced digital signal processing methods will be developed to analyse the nature of these interference waveforms so that they can be accurately reproduced using new testbeds to assess the range of European smart meters. These methods and apparatus will form the new type-approval tests and normative protocols to restore confidence in electricity metering.

With 200 million smart meters rolling out across the EU, the suggestion in recent studies of over-billing by some 500 % when meters are exposed to certain interference, threatens to undermine consumer confidence in this €45 billion EU mandated roll out. This is particularly alarming as all erroneous meters were already tested and approved under the EU’s measuring instrument directive (MID).

Field measurements are needed to capture the real-world interference that appears in typical houses, along with interference generated by the newest home appliances. This interference is highly complex and continuously changes severity, so new methods are needed to trigger its capture and to break the resulting waveforms into their constituent parts. This requires new mathematical algorithms based on the methods used to detect defects in cardiac waves or as used in computer recognition of images.

The distilled interference must then be regenerated in the lab in a reproducible way and used to test all types of EU smart meter under identical conditions to see if any meters give significant errors. This will require the development of new testbeds to generate the waveforms, which together with the most problematic interference, can form the basis of new normative testing methods for the MID. Interference immune “benchmark” meters are needed to resolve consumers billing disputes and can be selected from these tests.

This is a joint research project carried out in the framework of the European Metrology Programme for Innovation and Research (EMPIR) (see:http://www.euramet.org/research-innovation/empir/). The EMPIR initiative is co-funded by the European Unions's Horizon 2020 research and innovation programme and the participating states. METAS is one of the project partners in the project.

Projektziele (Englisch)

1. To provide and characterise metrology grade sampling digitisers and transducers and use these to determine the nature of disturbing and interfering signals present in typical electricity networks, both in the lab and on-site. This will lead to the definition of accuracy boundary conditions for static electricity meters during use.
2. To develop new measurement algorithms to accurately measure ac power/energy in the presence of highly impulsive current signals. To furthermore develop and/or optimise non-stationary waveform transforms such as time-frequency distributions and wavelets to determine the parameters of typical disturbing currents such that they can be accurately classified and re-generated for type-testing of commercial smart meters. Implement the algorithms in a reference signal analysis tool suitable for diagnostic use by non-specialists to analyse disturbing current signals.
3. To develop a standard measurement testbed for testing static electricity meters with a target uncertainty of better than 0.1 %. The testbed will use the outputs from objectives 1 and 2, and together with a phantom power arbitrary signal source should provide reference power/energy measurements to match in-service conditions.
4. To develop new type-tests and validated methods for determining electricity meter performance and to modify and characterise a reference “benchmark meter” for use in consumer metering disputes. This includes the identification of the most appropriate test signals and the testing of a range of static electricity meters using the testbed developed in objective 3.
5. To contribute to the standards development work of the CEN and IEC technical committees, CLC/TC 13, CLC/TC 205A, and IEC/TC 13, IEC/SC 77A and the legal metrology organisations WELMEC and OIML to ensure that the outputs of the project are aligned with their needs, communicated quickly to those developing the standards and to those who will use them, and in a form that can be incorporated into the standards at the earliest opportunity.

METAS contributes to WPs 1, 3, 4 and 5.

Abstract (Englisch)

The accuracy of electricity meters can be affected by interference generated by equipment connected in the building that the meter is measuring energy. The nature of disturbing and interfering signals present in typical electricity networks needs to be determined in order to define the accuracy boundary conditions for electricity meters during use.

The extent and type of interference typical in low voltage mains is measured at various meter connection points in various European countries by using digitising equipment and transducers with sufficient dynamic range and resolution to capture the current waveforms in substations and consumer installations typical of those present at metered supply points.

The current waveforms from a selection of consumer products that contain power electronics will be procured are also captured to further identify the signals of waveforms that induce meter errors.

Umsetzung und Anwendungen (Englisch)

The results acquired by METAS and other partners in the scope of WP1 and WP3 led to the organization of a final workshop involving at least 90 attendees. Partners, stakeholders and members of international committees presented and discussed the outcomes obtained in the various work packages. 
The discussions were mainly focused on the shape and validity of the perturbation waveforms that were analysed and reproduced on the various test benches. 

The possibility to observe highly perturbed current and voltage waveforms in a real-world sce-nario was a big concern amongst the workshop attendees. The selected perturbed waveforms that were inducing some error in the electricity meters could be backed up by on-site meas-urements and the accuracy of the waveform reproduction was confirmed with the uncertainty calculation on all testbeds.

 

METAS participated in the writing of two deliverables which summarize the design and usage of the testbeds as well as the waveforms used in those testbeds. Those deliverable aim to be used as a basis for a future normative type testing and they will be submitted to technical committees such as IEC SC77A.