Customer application 31 August 2020

Every Network Station under Control

RheinEnergie, an electrical supplier based in Cologne, has gotten a clearer view of the distribution network using the robust WAGO-I/O-SYSTEM 750 XTR. Its goal is to further reduce downtimes.

RheinEnergie regularly modernizes its local network stations (LNS), replacing old technology with new, as part of its contract with the network operator, Rheinisch NETZGesellschaft (RNG). This supplier now aims to do even more: The distribution network it to become more intelligent as well. “Our supply area is quite enormous. If a fault occurs in Lindlar requiring a maintenance team, during rush hour, for example, then it takes a good bit of time before they are on site,” explains Markus-Oliver Maitz, system planner in Technical Network Service at RheinEnergie. The maintenance team then has to locate the problem on site. If the control center can narrow the fault down to a single networks station, then the problem can be eliminated faster.

The Benefits of WAGO for You:

WAGO’s 750 XTR Controllers are rugged and compact and allow flexible extension
Address up to sixteen channels per control panel using different communication protocols
Easy connection between the controller and the telecontrol system

New Measuring Technology for Intelligent Local Network Stations

There are approximately 8000 LNSs in the region supplied by RheinEnergie, including private stations. “Our stations are modernized per the requirements of the strategic asset management of the network operator,” explains Thomas Otto, expert in design and controllers at RheinEnergie. In order to reduce downtimes, it is sufficient if three or four LNSs from one supply ring transmit the error direction, according to Otto. In these intelligent LNSs, “clever” measurement technology is not only the prerequisite for fast error location, but also forms the basis for the next step. “The installed telecontrol technology allows our colleagues in the cross-connected control center to carry out switching operations remotely. In the optimal case, at least half of the customers affected by downtimes are reconnected in a short time,” explains Otto.

Compact System

In the new switchgear units, WAGO’s 750 XTR Series Controllers ensure that everything functions as planned. “We wanted a compact control system that could maintain an overview of all necessary information and still be accommodated in a small control cabinet,” says Maitz, the systems designer, summarizing the challenges. It should also be inexpensive. High dielectric strength posed an additional challenge. The 750 XTR meets all these requirements – and more. Despite its compact design, the robust controller can address up to 16 channels per control panel using different communication protocols and forward the data. At RheinEnergie, this is carried out via Modbus TCP/IP. Short circuit indicators, ground connection indicators, circuit breakers or SF6 pressure loss – in all, the WAGO controllers manage around 50 messages and commands in the switchgear units for RheinEnergie.

One Single LAN Cable Instead of a Cable Snarl

“If you wanted to implement something like this earlier, you had to lay an individual cable to the telecontrol unit for each command,” explains Thomas Otto, head of planning. The resulting cable snarl confused even experienced maintenance experts. Now, one single LAN cable suffices to connect the controller and the telecontrol system. Information arrives at the control center from the telecontrol device. RheinEnergie does not use public communications, but rather relies on its own data network to transmit data from the LNS to the control center.

Customized Configuration

The switchgear units, including all primary and secondary technology, were delivered to RheinEnergie as a turnkey solution, so to speak. Basic equipment for each switchgear unit includes a fieldbus coupler, a mains filter and an end module – everything else depends on the individual demands placed on the local network station at the respective location. Each switchgear unit additionally has an uninterruptible power supply, which is supplied by two battery packs from WAGO. “The battery packs were configured exactly to our specifications by the WAGO experts. The system should operate for four additional hours during a power failure, and each field should be able to be switched three times” explains Maitz. Following the installation of the first system prototype in spring 2016, the technicians at RheinEnergie continue to install additional ones gradually. “The WAGO controller provides us with all necessary data; it is compact, especially suited to the environmental conditions and easy to parameterize; it can allows flexible expansion; and, above all, it is inexpensive – all of our requirements have been met in the best possible way,” concludes Maitz.

A Digital Makeover in Seven Days

It takes only one week to upgrade the average LNS with three to four digital control panels. The smart technology has been a fixed component of the station retrofitting program and is constantly being integrated into the LNSs. Gradually, over the coming months and years, additional intelligent LNSs will be incorporated into the control center at RheinEnergie, including all of the data that the WAGO controllers monitor on site. As a side effect, so to speak, the network also functions better with decentralized and volatile energy sources, like photovoltaic systems or wind turbines – because if the systems push too much power into the network to the point of failure and the power flows reverse, then the WAGO controller reports this, and the control center can react. “Our average downtime is currently less than eight minutes,” says Markus-Oliver Maitz. “This important parameter will soon be reduced again.”

Text: Daniel Wiese, WAGO

Photo: Niki Romczyk, alphadialog