Smart metering and smart grids are hot topics, in both European countries and worldwide. Chinese manufacturers develop these smart meters, but a problem arises because legislation in Europe differs from Chinese legislation. Therefore, NMi and VSL organized a successful seminar in Guangzhou, China, for manufacturers of watt-hour meters. Main topics included the situation in Europe concerning the Measuring Instrument Directive (MID) and the metering and measurement challenges of the Smart Grid.
Mr Chuan Wen, Senior Consultant for NMi, explained the more general aspects and structure of the MID with special focus on the background of module B (type approval) and module D (conformity to type based on quality assurance of the production process). This was followed by a talk on the specific technical and legal aspects of watt-hour meters in the MID. Henri Schouten, Senior Approvals Expert, discussed the changed terminology introduced by the MID, the new accuracy classes A, B and C, the composite error, and the new requirements on software. The harmonized standards, EN 50470, were also explained.
Software requirements for watt-hour meters
The specific software requirements as laid down in the WELMEC 7.2 guide were important to most manufacturers. In the well-known IEC-standards for watt-hour meters (IEC 62052 / 62053 series) no specific software requirements are laid down. However, for European approvals under the MID, several software requirements are mandatory. Aspects like protection of data, long-term storage, transmission of data, software separation and software downloads were discussed.
Tests for 2150 kHz
A specific EMC problem has been noticed recently in Europe with the 2150 kHz frequency range. This frequency range is not covered by the IEC standards nor by the EN-standards. Manufacturers have to guarantee that their meters operate properly in the conditions where their meters readings may be disturbed in this frequency range. Although no basic IEC standards are available for this phenomenon, NMi has already developed a test setup in order to simulate this occurrence.
Multidirectional energy supplies
Mr Zhao Dongsheng, Scientist Electrical Measurements at VSL, focused on the special aspects of Smart Grids. Environmental issues and diminishing energy supplies are challenging the traditional model of electricity generation and distribution. Conventional centralized grids can be thought of as passive one-way bulk energy systems whereas the Smart Grid systems are active systems consisting of multiple bi-directional energy clients. These distributed systems are highly complex, difficult to optimize and vulnerable to instability. This leads to a paradigm shift in the instrumentation and control requirements for Smart Grids, such that a stable, high quality electricity supply can be assured.
Successful implementation of a Smart Electrical Grid requires the development of a suitable metrological measurement infrastructure. The metrological challenges consists of suitable measurement tools to ensure security of electricity supply and monitoring grid stability in the transition from a conventional to a Smart Grid. As, in a Smart Grid, more parties will supply energy to the grid, not only via conventional power plants but especially via renewable energy sources such as wind and solar energy, an increased need arises for on-site determination of grid quality and on-site measurement of energy flows.
This seminar proved again that it is very useful to share information on legislation in Europe and aspects on the Smart Grids to pave the way in reaching vital solutions.
