18NRM05 SupraEMI: Grid measurements of 2 kHz-150 kHz harmonics to support normative emission limits for mass-market

• Forschungsstelle: METAS
• Projektnummer: F-5213.30120

Schlüsselwörter (Englisch)

Power quality, supraharmonics, EM emissions, EM compatibility, impedance measurements, transducers, waveform metrology, waveform transforms, algorithms.

Kurzbeschreibung (Englisch)

The overall aim of this project is to develop new normative measurement techniques to enable regulation of interference caused by mass-market electrical products. The build-up of product emissions in the supraharmonic frequency range of 2-150 kHz, threatens to cause malfunction of other electrical products, power line communications, and critical infrastructure. Unlike other frequency ranges, the supraharmonic band has no effective regulation or normative measurement framework. This project will work with standards committees to develop a new measurement framework to facilitate the setting of realistic and credible supraharmonic interference limits and enable the regulation and compliance testing of mass-market goods.

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)

The overall objective of the project is to develop a measurement framework for supraharmonics in the electricity network, such that realistic, credible and measurable procedures for compliance assessment can be incorporated into normative standards.

The specific objectives of the project are:

1. To formulate a new normative method to measure supraharmonics (2 to 150 kHz) in electricity networks suitable for inclusion in the redefinition of IEC 61000-4-30 Edition 4, and which should be compatible with the method defined by CISPR 16, which is only appropriate for equipment emission measurements in laboratory. In addition, to implement the new method using suitable portable and traceable instrument(s) to measure voltage and current in the supraharmonic frequency range with accuracies of ≤ 1 %.
2. To validate the new method by conducting a laboratory comparison of the new method with the existing methods in IEC 61000-4-7 (2-9 kHz) and CISPR 16 (9-150 kHz) using the respective artificial mains networks (AMN) to represent the impedance of the electricity network, and examining emissions from a selection of electrical appliances.
3. To determine the suitability of supraharmonic compatibility levels (as defined in IEC 61000-2-2) by measuring the emissions from a selection of electrical appliances connected in a selection of LV networks. To use these on-site LV network measurements and to compare with the laboratory measurements to determine the suitability of the AMN approach as a realistic laboratory representation of LV network conditions.
4. To verify the applicability of the AMN characteristics by measuring network impedance characteristics of a number of typical LV electricity networks with a target uncertainty of 5 %. Measurements below 9 kHz will be used to verify the IEC 61000-4-7 AMN and measurements in the range 9 to 150 kHz will be used to verify the CISPR 16 AMN.
5. To contribute to the standards development work of the technical committees IEC SC77A WG 1, 8 and 9, and CISPR 16 by providing recommendations on improvements to supraharmonic measurement methods (4-30), and the normative specification for the AMN in-line impedances (4-7 and 2-2) as well as how these new methods should be applied to compare levels measured in the electricity network with supraharmonic compatibility levels (2-2), and ensure that the outputs of the projects are aligned with their needs, communicated 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.

Abstract (Englisch)

The project SupraEMI is intended to give a significant contribution to the revision of the EMC standard IEC 61000-4-30 that defines the methods for measurement and interpretation of results for power quality parameters in AC power supply systems with a declared fundamental frequency of 50 Hz or 60 Hz. In particular, the project aims at extending the measurement range from 9 kHz to 150 kHz, thus including many disturbances related to modern smart grids, like electric vehicle chargers, photovoltaic installations and - more generally – any electrical component connected through a power electronic-based inverter.

Before introducing new regulations and emission limits, it is necessary to define rigorously what is the reference measurement method and the parameters to be identified. The simple extension of existing method is theoretically viable, but practically unfeasible as it would produce unacceptable computational complexity and amount of data to be processed.

After having identified a promising algorithmic approach, the current stage of the project consists in assessing its performance in standard and off-standard conditions. In this context, the algorithm has been widely tested through numerical simulations in Matlab. Next steps will be the implementation of the same algorithmic procedure on a stand-alone industrial controller, e.g. a National Instrument compactRIO, that would allow to have a portable supra-harmonic measurement unit (in view of a reference instrument and/or field measurements).