Since 1993, all monitoring and control operations for LINZ AG Wasser’s 29 wells, 31 water storage tanks and 60 pumping stations have been performed from a central control station loca-ted at the Scharlinz waterworks. To date, however, only part of the measured data needed for automated process monitoring and control of individual distribution zones and supply lines was transferred to Scharlinz and pressure surges, elevated tanks and waterwork installations were still managed on site in a 24-hour shift system.
Start of modernisation activities in 2007
Due to the availability of new processing and process control technologies and the changing requirements in asset management, the decision was made in 2007 to upgrade all water supply operations with state-of-the-art automation technology. The first step consisted in a technical adaptation and restructure of the process control system. The new system was to support all necessary process control and monitoring functions, assure a seamless documentation of flow charts and important dispatch operations, execute, monitor and optimise water distribution processes and keep statistical records of all energy-related and operational data.
To enhance system safety, the new graphical controls had to be fully redundant. All monitoring and control processes had to be executable from a mobile device as well as from the control station.
The project was to upgrade the system’s control technology as well as to improve transfer and remote control technologies and revamp the technical infrastructure of 85 water distribution units. The project team was faced with a number of operational challenges as ongoing control processes were to remain unaffected by the control technology and infrastructure upgrade.
Start of second project phase in 2010
After commissioning the system and upgrading the remote control system and technical infrastructure of all important supply units, the project team launched the second phase in 2010. Phase II was aimed at the full automation of all water supply operations.
The objective was to reduce the dispatcher’s operational workload to regular work hours. Free capacities resulting from the termination of shift operations were to be used to cope with the growing challenges of asset management.
In developing a concept for technical implementation, the project team also took account of the technical background conditions including system control, distribution zones, analysis and classification of alerts etc. as well as all organisational and human resource aspects. The concept comprised the following:
- automation of waterworks and primary elevated tanks;
- automation of zone couplings (automation within the zones by means of a hierarchical model) and
- execution of automatic and (optionally also) ma-nual operations in the various zones.
With a view to the system architecture, automation had to be kept simple to allow process traceability at all times. All automation functions in the control -system are hierarchically arranged and grouped in modules. They are sub-divided into:
- a system level (corresponding to the entire distribution system),
- a distribution zone level (corresponding to the distribution zones),
- a unit level (e.g. waterworks),
- a sub-unit level (e.g. well fields and wells) and
- an equipment & supplies level (e.g. pumps, valves).
Automation follows a clearly defined principle (example: tank management). There are various different autarkic distribution zones, each of which is serviced by one water tank and the pertaining waterworks. The difference between the actual water level inside the tank and a predefined level is determined to calculate the required pumpage for the individual waterworks. The waterworks connected to a water tank have to achieve the required pumpage. A number of technical parameters, such as system pressure or flow volumes, need to be taken into account.
Project successfully completed in November
The automation of the water distribution system in Linz was successfully completed in late Novem-- ber 2013 after a testing phase of several months. - e 1.9 million were invested in the project. “Both customers and employees at the Scharlinz control station will benefit from the upgrade. Our staff no longer has to work shifts and weekends, which dramatically improves their quality of living. The project has also significantly enhanced the efficiency of our water supply operations and improved quality assurance,” concludes Reinhold Plöchl, head of department at LINZ AG Wasser.
LINZ AG is the leading Upper Austrian energy and infrastructure provider group for energy, telecommunications, transport and public services. The catchment area of LINZ AG Wasser comprises the city area of Linz as well as 21 surrounding communities. Including the daily commuters, the company supplies a population of 400,000 with water. The water distribution volume amounts to 22.4 million cubic metres per year.