This project will demonstrate on-site metrology-grade measurement of the key parameters of trial DC grids. This demonstration of traceable measurements made on-site will support the methods uptake by end-users and will help to pave the way to the eventual large-scale roll-out of DC grids and such technologies.
In order to provide the necessary information for Distribution Network Operators, DC grid trials need to be properly designed. This project will support the appropriate design of DC grid trials by developing an industry guide so that DCPQ “planning level” surveys can be reliably performed. Further to this, DC grid trials require special permissions from Energy Regulatory Authorities because they deviate from present regulations. One of the outcomes of this project will be an industry guide on compatibility and planning level surveys of DCPQ in LVDC grids which will be beneficial for utilities companies and authorities and will help them to reliably perform future level surveys.
To meet future demand, energy suppliers will need to install enormous amounts of DC electricity meters. Therefore, the reliability of these meters is extremely important, especially when the meters are exposed to PQ disturbances. The metrological infrastructure to be developed by this project is a prerequisite for Notified Bodies to perform type approval for Meter Manufacturers which in turn is essential for proving reliability as required by EU regulation. To help support this, the project will produce an industry guide on proposed test waveforms for DC electricity meter testing.
This project will directly liaise with energy suppliers and stakeholders via the formation of a stakeholder committee. This group will include representatives from network operators, industry, academia, and standardisation bodies, and will help the project’s results to directly impact such representatives.
In addition, this project will also involve site owners and utility companies via measurement campaigns of DC power and DCPQ parameters at real LVDC grids and facilities. This will be done to promote the real-world applicability and uptake of the project’s results by the energy suppliers.
This project aligns with the strategic research agenda for EURAMET’s European Metrology Network (EMN) on Smart Electricity Grids and is supported by the EURAMET Technical Committee on Electromagnetic Metrology (TC-EM). The new reference setups developed by this project for DC power and energy and DCPQ will provide the missing metrological infrastructure for these quantities. This will allow NMIs to propose new (and much needed) CMCs and future intercomparisons for DC grid measurements. In addition, new reference DCPQ setups will be implemented on DC-specific PQ parameters such as ripple and in-rush. Such reference set-ups are needed for NMIs to be able to provide the assured traceability required by Notified Body testing laboratories and legal metrology verification authorities.
The application of this project’s DC grid measurement techniques and the definition of DCPQ events and related metrics will be of great interest to the wider scientific and metrology community dealing with DC distribution grids. To support the transfer of this knowledge, at least four open access papers will be submitted to peer-reviewed journals and the project’s results will be presented at scientific conferences. The project also plans to host two workshops; one on on-site measurements in LVDC grids and their interpretation, and one on new metrology for LVDC grids and DC metering, respectively.
Links with the most relevant standardisation working groups have been initiated: IEC SC77A WG8, IEC TC8 WG9, IEC TC13 WG11, and CLC TC13 WG01, have been informed about the project and its objectives. Further relevant IEC WGs for DC metering have also been identified and initial contacts have been established.
The reference equipment for DC metering and DCPQ developed in this project is expected to lead to valuable input for standardisation on DC grids. For example, CLC TC8X WG1 is presently working on DCPQ parameter limits for implementation in EN 50160 on voltage characteristics of electricity supply grids. In addition, IEC TC8 JWG9 is developing a document on the assessment of standard voltages and PQ requirements for LVDC electricity distribution.
The new measurement techniques for DC metering developed in the project will also support EU regulation i.e., Directive 2014/32/EU (the Measuring instruments Directive or MID), as well as IEC TC13 WG11 which is presently working on a first edition of the IEC 62053-41 on specific requirements for DC electricity metering equipment. Further to this, the outcomes of this project will be disseminated to IEC SC77A WG9 which oversees IEC 61000-4-30 on the definition of AC PQ parameters and will be adapted in the future to include DCPQ parameters and IEC TC85 WG20 which is responsible for IEC 62586-2 on the measurement equipment and test methods for PQ in power supply systems as defined in the IEC 61000-4-30.
Finally, the results of this project will also be important input to IEC TC8, CLC TC13 WG01, IEC/CISPR/CIS/H/JWG6, IEC SyC LVDC, IEC SC77A WG1 & WG2, CEN/CENELEC/ETSI SG- CG, WELMEC WG5, WG8 & WG11, CIGRE/CIRED C4.40, IEC TC38 WG47, IEC TC38 JWG55, EURAMET TC- EM and BIPM CCEM.
Many claims have been made over recent years regarding the advantages of moving to DC distribution networks, but such a conversion is an immense investment decision for a highly conservative electricity industry. The PQ compatibility and planning level surveys developed in this project are essential for supporting the success of DC grid trials and increasing confidence in the resulting benefit analysis from the trials. Thus, supporting the future rollout of DC grids by the electricity industry.
In the future, it is expected that through the operation of electrical products via DC grids, Europe can improve its energy efficiency, reduce manufacturing costs and temperatures by obviating the need for transformers and power electronics. Whilst initial redesign and implementation costs will be needed for this, the longer-term cost benefits for European consumers and manufacturers should outweigh this. For example, by removing conversion stages (AC to DC or DC to AC), this will improve energy efficiency, reduce energy losses, and reduce material usage (i.e., fewer copper transformers, and fewer wall chargers). In addition, reduced network reinforcement costs brought about by better and smarter use of networks will reduce the costs passed on to electricity consumers.
In the long term, the efficient integration of renewables (photovoltaic cells, heat pumps) and EVs into DC grids integrated with local storage will become the ideal model for distributed energy generation. Such distributed energy generation should increase fuel supply security and, in some cases, improve supply reliability. Therefore, the use of DC grids is already attracting attention in hospitals, shipping, and other community projects.