The European Committee for Electrotechnical Standardization, Cenelec, has accepted the transport profile of Siemens' distribution line carrier communications protocol, CX1, as a standardization proposal. As the basis for the transmission protocol, which uses the low-voltage network as a communications channel for data of grid sensors and smart meters, the transport profile has been designed to ensure interoperability in accordance with EU Mandate M/441. CENELEC Committee TC 13 will forward Siemens' CX1 transport profile to Committee TC 57 of the International Electrotechnical Commission (IEC) as a proposal for inclusion in the IEC standardization process.
"For us, this is a big step towards a standard for open and fault-tolerant communication via powerline in intelligent power supply grids," says Jan Mrosik, CEO of the Smart Grid Division in the Siemens Infrastructure & Cities Sector.
In addition to grid sensors, distributed installed for collecting of grid status data, intelligent meters can also be used as information and communications gateways in domestic households. The devices not only record energy consumption data, but also collect data about network quality, which are relayed to the utility provider's energy management system. The data are then used to monitor the grid. Distribution line carrier protocols such as Siemens' CX1 use existing power lines to transmit information on the grid and consumption. This means that energy providers are able to save the costs involved in providing additional communications infrastructure.
CX1 is based on spread spectrum modulation, in which multiple frequencies within the same frequency band are used simultaneously to transmit a single signal. This means that interference, which often occurs at certain frequencies, has only a negligible effect on signal transmission. In addition, the communications protocol can handle any change in the physical communication parameters of a low-voltage power supply grid, such as signal attenuation, noise, network disruption and signal coupling, as well as operational changes in network configuration. The protocol also offers room for maneuver in terms of integrating additional transmission protocols and future smart grid functions, such as the secure transmission of load control signals or the transmission of network quality data. Furthermore, it can be integrated into existing IEC-protocol-based network automation and energy management infrastructures.
The powerline protocol CX1 is already used to connect meters and other intelligent terminal devices in Siemens' Smart Grid metering systems, such as in the load-switching devices which will replace household ripple-control receivers. The systems collect energy consumption data and network information, which are then relayed to a control center for further processing.