Siemens Energy has opened up smart metering communications for meters produced by other manufacturers by developing a proprietary Distribution Line Carrier communications protocol. Manfred Unterweger, head of product management for Smart Metering Products in its Power Distribution Division, explains.

Manfred Unterweger, Siemens, Germany

In the early part of this year, Siemens Energy opened up its previously proprietary Distribution Line Carrier (DLC) communications protocol, which utilizes the low-voltage network as a metering communications channel. This give utilities the opportunity to also deploy meters produced by other manufacturers within its automated metering and information system (AMIS). By opening up its DLC communications protocol, Siemens Energy is setting a milestone in the direction of open communication with smart meters, and therefore taking a first step towards establishing a new standard in high-efficiency metering communications via power lines.

Siemens Energy offers holistic smart metering solutions based on AMIS as a key component of Smart Grids. Important features of this system are smart meters that can transmit consumption data and load profiles via the low-voltage network to a central data processing station. For this automatic telemetering via the low-voltage network Siemens has developed a proprietary DLC communications application based on spread spectrum signal modulation. With this form of modulation the frequency actually required for signal transmission is increased.

This is known as spectral frequency spreading of the transmission signal. This means that a narrow band signal is transformed into a broadband signal, which covers the entire frequency range between 9 Hz and 95 kHz defined for communications.

Interference signals, which as a rule occur at certain frequencies, only have a very minor effect on signal transmission. This makes this communication practically insensitive to interference signals and distortion. In addition, the DLC communications application can handle all changes in the physical communications parameters of a low-voltage supply network such as signal damping, noise, network disturbances, signal coupling and changes in the network configuration.

To ensure the quality of the signal transmitted to all connected smart meters is sufficiently good, the application supports dynamic, adaptive signal routing, which means the transmitted signals are automatically routed by the connected terminal devices to the next one. The developed application thus enables almost full availability of this communications technology. In real operation almost 100 per cent accessibility of the connected meters can as a rule be achieved. The protocol thus ensures trouble-free functioning of smart metering solutions within a Smart Grid. The application also offers sufficient scope for integrating future Smart Grid functions, such as reliable transmission of control signals for load control purposes and the transmission of network quality data. It also enables incorporation of an existing network automation structure based on IEC protocols.

Siemens Energy offers holistic smart metering solutions based on its automated metering and information system AMIS as a key component of smart grids

With the increase in the feed-in of power from renewable energy sources into the grid and the associated need to control consumption directly on the consumer side, smart meters will increasingly develop into multifunctional smart grid components. To be equipped for the future Siemens recommends deployment of meters based on digital signal processor (DSP) architecture.

This hardware design also allows the activation of future developments in Smart Grid communications protocols. It also allows further refinement of the metering functions of the meter itself, for example the metering of grid parameters and communications functions within households. This takes place without having to directly access the meter via a software download from a central point.

The Siemens DLC communications protocol has a proven track record as part of smart metering and Smart Grid solutions such as those implemented at the European utilities: Energie AG in Austria, Arbon Energie in Switzerland and EnBW Ostwürttemberg Donau Ries AG (EnBW ODR) in Germany.

AMIS implements end-to-end communications, from the terminal device to the control centre

Holistic smart metering as the basis for smart grids 

In September 2010, at the Metering Europe conference and exhibition in Vienna, Austria, Siemens Energy presented a holistic smart metering solutias a key component for setting up Smart Grids. This solution consists of an AMIS automated metering and information system, and an Energy IP metering management system.

As a data hub Energy IP integrates existing utility IT systems via an SAP-certified interface into the smart metering infrastructure. Utilities can thus use smart metering across their business – from metering to billing and from operations control to network planning. Siemens Energy is one of the few companies that can offer one-stop holistic solutions like this.

Using sophisticated hardware and software, the Siemens smart metering solution AMIS offers support at every level of the distribution network, from network management to the multifunction meter

This smart metering solution offers a future-proof basis for tomorrow’s Smart Grid applications, which will help to handle the increased feed-in of renewables-based power. The core tasks include remote reading and management of all meters in a supply area. Gas and water meters communicate bidirectionally via Siemens smart AMIS meters. Existing ripple control systems can be replaced with the new technology.

Furthermore, utilities can use the system to record network parameters such as over and under-voltage, short and long-term failures, and power quality indicators from the medium-voltage network and at the end customer. On the basis of detailed information such as ground fault and short-circuit displays, and measurable asset indicators, network operation as a whole can be optimized. Additional services such as gas and water metering are also possible.

With its smart metering portfolio Siemens Energy meets the requirements of utilities at various levels along the value creation chain. A range of solution modules supports network-wide process automation. This includes integration of the meters, data concentrators and transaction servers of the AMIS automated metering and information system, and the linking up of utility IT systems to the Energy IP data hub – the metering management system of Siemens’ partner eMeter. Solutions for telecontrol of the low-voltage network, monitoring of network quality and support for mass installation of electronic meters complete the portfolio. Special IT solutions ensure network-wide process integration in the branch IT solution SAP Utilities.

This integration is based on a service-oriented architecture, which exchanges measured data, alarms and control data bidirectionally between SAP, Energy IP and third-party systems such as load management, outage management and job order processing. The metering management system is the neural hub of the smart metering infrastructure. These data and process integration enable utilities to optimize their administrative business processes and at the same time to intensify customer support.

Real load profiles instead of relying on statistics

At Metering Europe an exhibit showed how Siemens Energy integrates the Energy IP metering management systems as part of a holistic smart metering solution via the SAP-certified MDUS (Meter Data Unification and Synchronization) interface into an existing corporate IT environment. That applies both to Siemens AMIS smart meters and to meters supplied by other manufacturers.

One of the interfaces on display enabled a flow of information and transfer of commands between SAP and the metering management system, while another interface demonstrated the flow of information in the direction of network planning.

With its network planning tool Sincal Siemens showed in Vienna how the metering management system can use cumulative measured data instead of statistically postulated consumption data as real consumer load profiles for network planning and simulation in order to provide a more precise basis for computation. The use of actual consumption data will become ever more necessary the more renewable energy-based power is fed into the grid, and when increased amounts of electrical energy are drawn at night, for example to charge electric vehicles.

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