Wiring Up Amsterdam, the Old Fashioned Way
02 November 2009
Fibreoptic networks and wireless radio transmission are often used to extend industrial networks when larger areas need to be covered. However these technologies may be expensive to install—especially in the middle of a large city like Amsterdam. In this case, some simple extension equipment, using copper wiring, proved to be a lower cost solution.
The Amsterdam Extension
Fibreoptic networks and wireless radio transmission are often used to extend industrial networks when larger areas need to be covered. However these technologies may be expensive to install—especially in the middle of a large city like Amsterdam. Some simple extension equipment, using copper wiring, might be a lower cost solution.
This situation was faced by Alliander (formerly Nuon) a Dutch energy company that serves more than 2.8 million private and business customers in the Netherlands, Belgium and Germany. The company deals with both gas and electricity. It generates 20TWh of electricity annually and distributes it, along with gas in its pipeline network, to a major part of the Dutch domestic and industrial market.
Amsterdam became a special problem for Alliander because it is a city with a large concentration of gas substations that need to be regulated as a network.
There is a requirement to not only regulate the substations across the Dutch capital, but also to monitor in real-time alarms, energy usage, and flow measurement. Management at Alliander believed that with this information, they could deliver better services to their customers and at the same time reduce costs.
One of the divisions of Alliander is Liandon (which was formerly known as Nuon Tecno). This engineering and project management division was contracted to provide a telemetry system for the gas network in Amsterdam.
Transmitting gas to Amsterdam's industrial and residential customers
For the remote telemetry unit Alliander chose a new RTU, the D05 from Datawatt Telecontrol Systems that utilises the Ethernet based IEC 60870-5-104 communication protocol. This is an IEC standard communication profile for sending basic telecontrol messages between a central telecontrol station and telecontrol outstations, which uses permanent directly connected data transmission lines.
Fibre or copper?
Using fibreoptic cabling for the Ethernet communications would have been the logical choice because many of the Ethernet links would exceed the maximum 100 m range for UTP (unshielded twisted pair) cable, which is the most common form and least expensive form of wiring for TCP/IP networks.
However, engineering managers at Liandon decided that fibre would be too expensive and nearly impossible to install in a short time frame and in a crowded city.
The solution was simple and ready-made: make use of the copper cabling which already existed in Alliander´s own telecom and signalling cable network.
This would, however, necessitate some extension work.
Racks of Westermo network extension equipment. Two DDW-221s are seen down below, with the DDW-100 SHDSL Ethernet Extenders above
“After some successful tests with the Westermo DDW-100 and our previous experiences using the Westermo modem family, Alliander made a choice to use the Westermo Ethernet Extender products,” said Mr. Rens Dekker, Senior Engineer at Liandon.
The key specifications were the galvanic isolation, extended temperature and performance of the DSL-line (digital subscriber line). Tests were done up to 17 km. Alliander is using six DDW-221s to form a central, redundant ring.
From this central ring 140 point-to-point communication lines are used to connect the remote gas substations. Each point-to-point link consists of two DDW-100s to extend the Ethernet link up to a maximum of 12 km.
The DIN-rail mounted DDW-100 is an Industrial Ethernet SHDSL extender, designed to work transparently for 10/100BaseTX networks on twisted pair cables. SHDSL is considered the best of several symmetric DSL technologies. This unit provides the ability to reuse existing twisted copper pair with data rates up to 2.3 Mbit/s in both directions up to 10 km. Since the DDW-100 is a bridge and not a router, it is relatively simple to install with all configuration done by DIP-switches.
In total Alliander has installed six DDW-221s and 280 DDW-100s to upgrade its gas distribution system into a modern, SCADA controlled and monitored communication system.
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