DLMS/COSEM over PLC – a hot item



Smart metering for residential customers, driven by market liberalisation, regulatory changes, technology advancements and the potential to better control end eventually help reduce energy consumption through better information to customers, is high on the agenda of metering people worldwide. Power Line Carrier (PLC) could be the number one medium for this purpose.

We have received strong market signals from all over the world, from actual and potential members of the DLMS UA, that DLMS/COSEM is seen as a suitable platform for standards for this new generation of meters to ensure interoperability – a must for large-scale rollouts and for enabling competition.

Responding to this need, the DLMS UA decided to add new communication profiles for PLC, with a view to offering the result for international standardisation to the IEC, using a fast track mechanism. A project team consisting of experts from leading meter manufacturers and some large utilities with a rich experience in using PLC has already met three times this year. The project builds on the results of the work of IEC TC 57, having developed the IEC 61334 series of PLC standards, and that of IEC TC 13, having developed the IEC 62056 DLMS/COSEM standards.

The IEC 61334 series specifies a number of lower layer PLC profiles, covering the physical and MAC layers of the OSI model. Since their publication at the beginning of this decade, they have been proven in the field over and over. The upper layers of the protocol stack, including the Logical Link Control layer and the Application layer based on DLMS, are common for all lower layers.

Although IEC 61334-4-41, the DLMS standard, specifies a general purpose object model, the COSEM object model, developed for energy metering and specified in IEC 62056-62, is much more suitable to model the required functionality of smart meters.

Therefore, the project team decided to merge the strong points of the two sets, taking the COSEM object model with the OBIS identification system as well as the COSEM Application layer from the IEC 62056 series, and the PLC media specific lower layers from the IEC 61334 series. The main points have been agreed on. Drafting of the standards has started and IEC standardisation work should be launched in the second half of this year.

Obviously, the Conformance Test Tool will be extended to cover this new communication profile. To date, 60 meter types have been certified to be ‘DLM/COSEM compliant’ and many more are expected in the near future; membership of the DLMS UA is approaching 100.

Please contact us for more information about the DLMS User Association at Pre-de-la-Fontaine 19, CH-1217 Meyrin-Geneva, Switzerland, e-mail: dlms@dlms.com, www.dlms.com.
Győző Kmethy, President Paul Fuchs, General Secretary