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Innovative fault signaling system for substations

Significant space and cost savings


High-voltage equipment at EAM

  • When systems are used over a long period of time, there is a distinct possibility that replacements may no longer be available for certain installed components.
  • E.ON Mitte AG was faced with just this challenge when it came to its fault signaling panels.
  • Employees from the company therefore worked together with Phoenix Contact to develop a new, more cost-effective and future-proof solution.
The modular controller adapts flexibly to the relevant application requirements  

The modular controller adapts flexibly to the relevant application requirements

Processing, storage, and transmission of signals via a communicative small-scale controller

The fault signaling panel is based on the long-established proven Inline automation kit. The digital and analog signals of the substation, unit substation or local network station are forwarded to the ILC 171 ETH 2TX small-scale controller via corresponding standard modules. The Inline controller, which has two Ethernet interfaces and an SD memory card, processes the data and links it to the respective variables for the control engineering. The data is then transmitted either via IEC 60870-5-101/-104 to the remote control head of the station – where present – or directly to the control room.


For more than eight decades, Kassel-based E.ON Mitte AG has been providing a safe and reliable energy supply to around 1.5 million people in the heart of Germany. The company's network area spans a total of 45,828 kilometers, covering large areas of Hesse, South Lower Saxony, and parts of East Westphalia and West Thuringia.

Around 1300 personnel are responsible for maintaining 19 kilometers of high-voltage cables, 9749 kilometers of medium-voltage cables, and 23,510 kilometers of low-voltage cables, in addition to other activities. Founded on September 6, 1929, E.ON Mitte AG has worked in partnership with districts and communities, continually establishing and expanding the supply of power and natural gas in the region. The company now has a network capacity of 8147 gigawatt hours. Substantial investment in the networks as well as the associated infrastructure, such as 70 substations and 6487 local network stations, ensures that consumers are reliably supplied with the energy they require.


Proprietary solutions limited in function were previously used

In substations, the secondary technology – namely the control engineering and control technology – is usually modernized after 20 years of service. By this point, some of the installed components are no longer available, as the manufacturer has either discontinued the devices or ceased trading. One example of this: the fault signaling systems that E.ON Mitte had previously purchased from two renowned companies in the energy and utilities industry. The systems installed in the substations are no longer offered by either manufacturer.

Fault signaling systems are used to visualize pending messages in substations and to forward them to the network control room. In the past, these systems were equipped with illuminated fields and relay technology and, depending on the size of the substation, consisted of a fixed number of indication fields, e.g., 40 to 80 fields. The fault signaling systems generated individual and group error messages, with it often being the case that only a group message could be transmitted to the control room. However, staff were unable to determine the type of fault based on this information. This meant that they first had to drive out to the relevant substation and so did not always necessarily have the correct replacement parts with them. The previous fault signaling systems were also proprietary solutions and often limited in function. This meant that it was very difficult or even impossible to back up the accumulated data in the case of some solutions. In various stations, analog values such as current, voltage or transformer temperature were recorded on paper. Personnel then collected the paper rolls on a regular basis so that the data could be evaluated in the network control room.   

Joint development of a cost-effective and future-oriented fault signaling panel

With all this in mind, Lars Wieddekind, who works in the Network Technology division of E.ON Mitte AG approached Phoenix Contact, the company's preferred supplier, with a view to finding an innovative, cost-effective, and future-proof solution. The energy experts at the Blomberg-based automation specialist, which has worked in the energy industry since it was established in 1923, received the requirements at the start of 2012 and from these developed a customer-specific solution based on the proven Inline I/O system. In March 2012, the first fault signaling panel was tested in the Baunatal substation on a trial basis. Both teams uncovered a few errors in the software and found additional areas for improvement. Once these were implemented, the fault signaling system went into normal service in the Haiger substation in September 2012.

Since the start of 2013, five additional systems have been installed in various substations. Additional panels are in the planning stage. The first fault signaling systems comprise 40 digital signals without 110 kilovolt switchgear or 80 digital signals with 110 kilovolt switchgear. The specialists are currently working on extending the scope of functions to 120 signals. Furthermore, they have been able to exploit additional optimization potential and promptly meet the requirements of E.ON Mitte.  

The error texts are parameterized easily via the web interface  

The error texts are parameterized easily via the web interface

Minimal adaptation of standardized error message texts

Using the controller's built-in web server, maintenance personnel can view the data on site in the substation on a web panel or notebook with integrated web browser. Phoenix Contact provides corresponding operator panels in the form of the WP 10T or WP 15T. The touch panels have a graphics-capable 10.5 or 15 inch TFT display, on which all relevant data is clearly visualized.

The HMI devices equipped with one Ethernet interface and two USB interfaces are characterized, among other things, by their compact design as well as their easy installation and fast startup. When delivered, standardized error message texts are preset on the fault signaling panel, which means that personnel usually just need to make a few adjustments via the web panel. In general, all necessary settings can be made via a PC with web browser or directly on the web panel. Custom message texts can, of course, also be defined – this does not require an additional PC and printer.

The display provides a quick overview of the error messages for the overall system  

The display provides a quick overview of the error messages for the overall system

The small-scale controller can be extended flexibly with analog input modules, which means that analog values can now be processed directly in the controller. The paper-based analog data recorder that was previously used is now obsolete. Furthermore, the individual signals can be easily set to operating current or closed-circuit current as well as visual or audible indication. In addition, the fault signaling panel can be easily integrated into the existing infrastructure of the substation, as no changes need to be made to the cabling or the transfer terminal strip.

All events are stored in chronological order. Even if communication with the control room is interrupted, the sequence of events in the station can be followed. This makes it considerably easier to find the cause of the fault. Provided the substation is connected to the same PIT segment (process IT network), personnel can detect the fault even if they are working in another substation.


Lars Wieddekind works in the Network Technology division of E.ON Mitte  

Lars Wieddekind, who works in the Network Technology division of E.ON Mitte, is thrilled with the jointly developed solution

The new fault signaling concept was developed in close collaboration with E.ON Mitte. As Lars Wieddekind explains: “Over the period of a year, we worked very closely with the team from Phoenix Contact. Thanks to their support during startup as well as their rapid response to software errors or change requests, we now have a cost-effective and future-proof solution in place. We are particularly pleased with how easy it is to change the message texts and that we have the option to communicate with the existing remote control head in the substations via IEC 60870-5-104.”

The team at E.ON Mitte were also very happy to see the amount of space required in the switchgear reduced by 60 percent.


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