SIEMENS

Water distribution networks are by no means an invention of the modern age. The Romans, for example, had an elaborate system of aqueducts to transport water over long distances. And towns in the middle ages built systems made up of hollowed-out tree trunks, water wheels, and water towers in order to supply their citizens with fresh water. In medieval Germany, this early form of hydraulic engineering was known as "water arts."
Some 500 years later, water supply networks really have become works of art. Often stretching over hundreds of kilometers, today’s networks are made up of an intricate combination of steel pipes, pumps, motors, valves, and automation technology equipped with intelligent software. The city of London, for example, has 4,800 km of mains that transport more than 630 million liters of water a day. This huge network, where over 30 % of the water is lost through leaks, is now in urgent need of modernization.
"The bigger the water network, the more complicated it is to operate," explains Tim Schenk from Siemens Corporate Technology (CT). In order to help water suppliers optimize their management of large-scale pipeline networks, Schenk, who represents CT’s "Modeling, Simulation and Optimization" Global Technology Field, is now working closely with Siemens Water Technologies (WT), one of the world’s leading suppliers of drinking water and wastewater treatment systems. WT installs turnkey water systems featuring automation technology from Siemens Industry Automation plus process measurement and control systems with pumps, motors, and pipelines. The result of the collaborative work between CT and WT is a virtual tool kit designed to enhance the management of water networks and monitor such networks for leaks.
At the heart of this effort is SIWA (Siemens Water) PLAN, a water management system used to calculate, simulate and efficiently control the massive volumes of drinking water and wastewater flowing through mains and sewer pipes (Pictures of the Future, Spring 2005, Fluid Information). CT has supplied WT with the models and algorithms for SIWA PLAN.
In addition to its use as an optimization tool for the operation of water infrastructures, SIWA PLAN can also be used for training. "Thanks to preinstalled fault scenarios, the system can be used to simulate what happens when, say, pumps or valves fail," explains Holger Hanss, product manager for SIWA PLAN at Water Technologies. When devising simulations for training needs, engineers construct a virtual copy of the customer’s network, including all associated automation technology, and then incorporate this into a software application providing a realistic user interface. In this way, future plant operators are able to hone their skills in a range of operational scenarios.

Digital Assistance. The training simulator, which was introduced in 2003 in the United Arab Emirates, was first used to create an exact model of a 180-km-long double-walled pipeline that connects a seawater desalination plant with several cities and which was to be commissioned at the same time as the pipeline itself. Today, the network is powered by eight pumps with a combined rating of 50 MW — the equivalent of the electricity consumption of a small town. With the help of the training simulator, it was possible to recreate, onscreen, the interaction between various operational procedures, numerous automation functions, and the flow of water in the system.
Compared to a pipeline, the water supply network of a major city like London is vastly more complex. Not only is the combined length of the mains enormous, but the complexity of the network itself means that without some form of computer support it would be virtually impossible to assess the impact of operational procedures on the pressures and flow rates throughout the system. This is the case when, for example, a water main has to be temporarily shut off for upgrading or enlargement of the network, which can result in undesirable consequences such as an increase in water pressure in nearby mains.
The planning, construction, and operational management of such networks present a special challenge. "Problems in harmonizing the control and automation technology are by no means uncommon," explains Dr. Andreas Pirsing, an automation and process control engineer at the Siemens Water/Wastewater Competence Center in Nuremberg, Germany, which is part of the Industry Automation Division. Indeed, until recently the only way of ascertaining whether the automation technology in a new water network actually functioned as specified in combination with all of a system’s innumerable pipes, pumps, and valves, was to build it and test it in the real world.
According to Pirsing, however, such difficulties should soon be a thing of the past. It was the experience gained from the UAE project that gave him the idea of using the process model from the SIWA PLAN training simulator for another purpose. "Our objective is to develop and perfect automation technology for a planned or upgraded water network on the basis of a virtual process model of that network. In this way, we can be sure that the automation technology and the network are perfectly coordinated, even before construction work begins," he explains.

Digital Library. In the manufacturing sector, virtual planning is already used to design, engineer, and test new products and their production processes onscreen (see Pictures of the Future, Fall 2007, "Factories of the Future"). Such an approach is, however, new for complete water and wastewater systems. As in other areas of industry, this use of virtual engineering cuts planning times, reduces costs for customers, and helps to prevent unwelcome and expensive system failures.
Just as importantly, the use of properly-matched automation technology substantially reduces water and energy consumption, which, in turn, benefits the environment. In fact, after airports, the supply of drinking water and the treatment of wastewater are the largest single sources of energy consumption in cities.
With a view to putting his idea into practice, Pirsing has been busy feeding his computer with benchmark data. But in order to avoid duplicating steps, he is currently creating "physical" models of all the components found in a water network — e.g. pumps, valves, and storage tanks — and storing them as software modules in a special digital library. "We can drag-and-drop these ready-made modules in order to rapidly put together a complex new water supply network for a major city onscreen or recreate an existing, antiquated system for the purposes of modernization," Pirsing explains.
In parallel, the real automation technology that will be used in the project is assembled using conventional engineering tools and then incorporated in the computer-based process model with all its virtual pumps, motors, and valves. Using virtual water flows, it is then possible to test the operation of the entire system with all its open- and closed-loop control systems. This includes an examination of potential incidents such as a pump running dry due to a valve being closed erroneously or leaks resulting from excess pressure in the system. Conversely, faults can be introduced — a stuck valve, for example — in order to test how the automation technology reacts. Once it has been demonstrated that the real automation technology is compatible with the virtual process model, the solution can go to the customer.
If all goes as planned, Pirsing will present a prototype of his integrated engineering tool in 2010. "Using this technology, we will be able to show the customer that a system functions flawlessly long before construction begins," he says. "That’s something completely new in the water industry."
Pirsing is confident that this system will help Siemens substantially increase its share of the €4 billion water industry. At present, the company holds around 10 % of the world market. "Siemens still has plenty of room for improvement in this area," says Pirsing, safe in the knowledge Corporate Technology’s researchers are currently redefining the art of water engineering.