Municipal drinking water and sewage management operations are obliged to ensure the safe supply of clean water and the disposal of wastewater 24 hours a day, 365 days a year. In order to accomplish this, reliable and flexible telecontrol solutions are needed. As part of a joint pilot project with HAMBURG WASSER (Hamburg Water Authority), WAGO developed a new telecontrol gateway (WTG) as an open interface between the field and control levels. After successful testing, HAMBURG WASSER now uses two of these gateways and 19 WAGO telecontrol substations in Germany’s Hamburg metropolitan area, with more to surely follow.
As a coordinating corporation, HAMBURG WASSER links the Hamburger Wasserwerke GmbH [Hamburg Waterworks] and the Hamburger Stadtenwässerung AöR [Hamburg City Sewage Public Works], making it Germany’s largest, municipally owned drinking water and wastewater utility. The primary functions of the enterprise include supplying drinking water and the proper disposal of wastewater in Hamburg and the surrounding environment. The latter flows from residential connections into a series of underground canals that form the city’s sewer network. This extends across an area of 300 km2, has a length end-to-end of more than 5,800 km and collects wastewater from approximately two million households, businesses, industrial customers and 28 surrounding communities. This creates a need for the continuous uptime of all technical systems, placing high demands on the safety and reliability of telecontrol technology.
Birth of the Pilot Project
The project began when HAMBURG WASSER sought to replace some of the telecontrol substations controlling the sewer network. When searching for a suitable solution to link the substations to the control system via secure dial-up connections, Claus-Ulrich Axt, Project Manager for Electrical, Measurement and Control Systems Technology at HAMBURG WASSER contacted WAGO, and the joint pilot project was born.
“My objective was to find a solution that would enable us to communicate using standardized telecontrol protocols. The end goal was to free HAMBURG WASSER from the technology of any single manufacturer. WAGO accepted the challenge and was ready to cooperate with us,” explains Axt.
Initial Situation: HAMBURG WASSER uses a control system for monitoring and controlling the sewer equipment. This system primarily controls the pumps and the telecontrolled gates that regulate the wastewater flow between the upper, local canals and the collection network, which is approximately 20 m below the ground. The connection to the telecontrol substations was partially handled by a proprietary telecontrol protocol using dial-up connections. The consequence of using these interfaces was the inability to incorporate telecontrol components from the leading manufacturers in control technology.
From Theory to Practice
specifications for the WAGO telecontrol gateway, ranking functions that were necessary, optional and possible in the future. Then they placed the first WTG into operation at one of two HAMBURG WASSER server locations in Hamburg. Over the following weeks, numerous tests were performed on the prototype, including Wireshark telegram recording and analysis, time synchronization and time stamps, as well as other IEC traces using tools such as WinPP. Interface adaptations to the control system were also made.
Once it was ready to deploy, the new technology was incorporated into the bid for replacing the telecontrol technology in the pumping station located in Hamburg’s municipality of Neu Wulmstorf. HAMBURG WASSER has been responsible for Neu Wulmstorf’s central wastewater disposal since 2008. In the meantime, two WTGs are operating redundantly within the project. This redundancy ensures greater levels of safety, since HAMBURG WASSER wants to prevent accidental wastewater release from polluting the environment, making it necessary to rely on the constant equipment uptime
The link between gateways and the control technology was established using a TCP/IP connection. In addition, HAMBURG WASSER has connected 19 WAGO telecontrollers (750-880/025-001) to the control system where they function as substations according to IEC 60870-5-101. Fourteen units function via analog dial-up connections, four via GSM and one via ADSL (which directly uses the IEC -104 protocol thanks to a redundant front-end computer system from the existing control technology).
“There were a few technical challenges that had to be overcome during the course of the project, including interoperability required by the IEC, redundancy behavior in coordination with the control technology manufacturer, time synchronization, correctly archiving data in the control system and error-free system configuration. Now, the WTG satisfies every demand that we expressed at the beginning of the project, and has proven itself in the sewer network’s operation,” notes Axt.
HAMBURG WASSER was assisted in implementing the project by ME-Automation Projects from Fuldabrück, Germany which oversaw delivery, installation, parameterization, programming and commissioning of the WTGs, telecontrollers and associated communication technology.
Innovative Combined Solution
The WTG, part of the finely modular and fieldbus independent WAGO-I/O-SYSTEM, consists of an I/O-IPC-C10 with WAGO telecontrol software that can link up to 64 telecontrol substations to the control level. The distinctive feature of this solution is that the WTG combines traditional programmable control with standard telecontrol protocols and an associated configuration tool, enabling the generation of IEC messages without requiring laborious programming. Thus, users can establish a standardized connection to the control technology and independently perform parameterization without specialized software.
Using Web-Based Management (WBM), operators can — within the parameters of their license agreement — add participants and make system adjustments. This simplifies the integration of telecontrol substations and eliminates unnecessary service costs from external contractors.
Up to twelve cards (RS-232 I/O modules) can be connected in series at the field level. Connections to the field level are provided via standard wiring, dial-up connections or transparent TCP/IP connection (DSL, GPRS router or TETRA radio modem), and to the control level via ETHERNET or GPRS. Connecting to substations using a dial-up connection to the gateway guarantees extremely reliable data transmission. Greater connection security than radio connections makes this is vital to critical installations like wastewater disposal.
Forward-Looking Telecontrol Solution
Following the successful pilot project, HAMBURG WASSER plans to gradually replace a significant number of the stations connected using dial-up connections to the new solution based on WAGO telecontrollers and telecontrol gateways. In fact, the municipal utility recently installed two additional WTGs and has ordered approximately 60 more controllers. These will be coupled to the WTGs using the IEC 60870-5-104 protocol.
“This demonstrates an additional strength of the WTGs. They were originally only conceived for dial-up stations and the IEC 60870-5-101 protocol; however, the WTG also supports the -104 version at the field level. This provides us with even greater flexibility. Overall, we are reducing our dependence on the control technology from a single manufacturer, giving us leverage in future negotiations. I have achieved my primary goal: the control and telecontrol technology at HAMBURG WASSER has been cost-effectively configured to be more flexible and more sustainable,” beams Axt.
Text: Kay Miller, WAGO
Photo: HAMBURG WASSER, ME-Automation Projects