Customer application 28 August 2020
Safe Pressure Regulation

People tend to think that at this point, the energy transition is limited to just the electrical sector. But DREWAG NETZ GmbH is going a step further and modernizing its gas distribution stations to bring intelligence to its gas division. For this process, the company relies on automation solutions from WAGO.

When smart grids are discussed, the focus is usually on the electrical sector, as is the case for the entire public discourse about the energy transition in general. In contrast, the gas and district heating sectors live in the shadows, at least as far as public perception is concerned. Yet adding intelligence is no less lucrative here. Recently, energy suppliers like DREWAG NETZ from Saxony have employed smart technology at the regional level in gas distribution systems. The I/O technology from WAGO’s 750 Series is used in an increasing number of gas pressure regulating stations in Dresden.

The Benefits of WAGO for You:

Ex i modules within the modular I/O-SYSTEM 750 have been designed specifically for hazardous areas.
880 ETHERNET telecontrollers support diverse ETHERNET protocols, such as IEC 60870, IEC 61850 and MODBUS (TCP, UDP, RTU)
Reliable, Simple and Economical

Data Transmission in the Connectionless Network

Tino Tietze, who oversees process technology and IT project organization, is responsible for the technology in the gas and district heating sectors. Under his leadership, DREWAG NETZ GmbH began expanding a proprietary process IP network based on MPLS (Multiprotocol Label Switching) in 2007. MPLS enables connection-oriented data transmission in an otherwise connectionless network. While the gas distribution is connectionless – i.e. there is no transmission in the opposite direction – a message connection between transmitter and receiver can be established in both directions for data exchange. This forms the foundation for a distributed system that has many advantages: Controlling and accessing all data of the connected system is possible from any linked in location. This increases fail safety. The entire system can be more easily scaled, so that output can be adjusted to demand at all times. Additional systems can subsequently be more easily connected, which could become even more important with greater decentralization.

Increased Functionality through Process Control Systems

Against this background, DREWAG NETZ GmbH began introducing a process control system throughout all pipe media in all control and dispatching centers starting in 2011. The pipe media include gas, water and district heat, as distinguished from electricity. The project was completed in 2016 and enabled an entire series of additional functionalities. For example, objects from different data recording systems can be represented and updated in a single image. Event protocols from all systems can be displayed in one window. System images can be retrieved from anywhere; alarms from all systems can be displayed and acknowledged. In this context, reliable communication is consistently established using the IEC 60870 telecontrol protocol.

Telecontrol Technology from WAGO is Performs Well at the Field Level

For process-related components, Tietze trusts the technology from WAGO, particularly where the actual measuring, controlling and monitoring takes place. Uninterruptible power supplies (UPS), signal conditioning modules and telecontrol technology from WAGO are found in increasing numbers of control cabinets in the DREWAG NETZ GmbH gas pressure regulating stations. The telecontrol technology, in particular, performed well in terms of cost-effectiveness, both for various telecontrol systems and in the subsequent field tests. 15 of these controllers are currently active in the supply area, and this trend will only increase, since the ICE technology is upgraded in an average of six gas pressure regulating stations per year. The controllers have been supplied by WAGO since 2013. “Ultimately, we were convinced by the reliability of WAGO’s telecontrol technology,” explains Tino Tietze.

Small, Practical, Good

The specific products in question are the 880 ETHERNET Telecontrollers in connection with Ex i modules, the so-called “blue modules” from the modular WAGO-I/O-SYSTEM 750 Series. The ETHERNET PLC can be used as a freely programmable controller in corresponding networks and is provided for use in industrial applications. In addition to a number of standardized ETHERNET protocols, it also supports IEC 60870, IEC 61850 and MODBUS (TCP, UDP, RTU). With two ETHERNET interfaces and an integrated switch, it ensures that no additional components, like switches or hubs, are needed. “Small, practical, good,” says Tino Tietze.

Ex i Technology Prevents Explosions

The “blue modules” are specifically designed, as part of the WAGO-I/O-SYSTEM 750, for use in hazardous areas and satisfy all specifications and safety standards. They ensure that no risk to the system arises from the electrical equipment used. Therefore, they are linked to the PLC in series, like the standard modules, and communicate with the actuators and sensors from Ex zones 0, 1 and 2. They provide a safe, easy and cost-effective connection. For example, if the gas pressure valve is actuated, the gas pressure can be changed through the telecontrol technology, or the gas temperature can be regulated without creating a risk of explosion. Cost-effectiveness plays a significant role here, since external Ex-barriers are unnecessary.

Fit for the Future

Thanks to the broad range of applications for the Ex i modules, from wastewater treatment plants to petrochemical plants, WAGO has gained profound expertise in the technical equipment required for hazardous areas. And gas suppliers are demanding such expertise more and more. This trend will only increase as technologies like power-to-gas or sector coupling gain even greater importance.

Text: Daniel Wiese, WAGO

Photo: Bildschön GmbH