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New Life for Historic Technology

Challenge

  • 2000, the hydropower system was restored too, but only ran for 18 months. “After that, it was at a standstill,” says Frank Petter. “Technical control problems were the main issue with it.”

Solutions

Results

  • Single programming environment
  • Faceplates made programming easier, while regular updates facilitate programming and reduce development time
  • Scalable solution offering easier expansion
  • Single HMI for the entire plant and rapid identification of issues thanks to HMI visualisation
  • Living museum attracts visitors to the town

Background

The hydroelectric power plant in the Neue Hütte technology museum – located in Schmalkalden in eastern Germany – stood silent for many years. Now, the local company Gesellschaft energetischer Projekte has breathed new life into the plant with a CompactLogix™ Programmable Automation Controller (PAC), part of Rockwell Automation’s Integrated Architecture platform

Getting old technology to work again is something that fascinates Frank Petter, who is an electrical engineer. That was why the hydropower system in the museum awoke his interest. Together with two business partners - a mechanical engineer and a master metalworker – he turned his hobby into a career and founded the company Gesellschaft energetischer Projekte (GeP). He is also its managing director. The firm specialises in the restoration and re-commissioning of old water mills and hydropower systems. “Our goal is to preserve historical technology for future generations,” explains Petter.

To do this, the company works with public bodies such as town councils or museums, as in this case. GeP wanted to reconnect the Neue Hütte technical museum’s hydropower system to the water network. They started by looking for an appropriate control solution – and found what they were looking for in the CompactLogix™ series of controllers. These are well suited to small and medium-sized machine applications.

Standstill in the Turbine System

At Neue Hütte, a neoclassical ironworks founded in Schmalkalden in 1835, local iron ore was turned into pig iron using coal up until 1924. Neue Hütte is one of the last examples of this technology in Central Europe. In 1921, the ironworks was extended with a turbine facility that used hydropower to generate electricity for machines and lighting in the factory. With a second turbine added in 1938, the hydropower plant continued producing electricity right up to the 1960s. Today, the building complex has been restored as a technology museum. It bears witness to the size and technical equipment typically found in an early industrial blast furnace. In 2000, the hydropower system was restored too, but only ran for 18 months. “After that, it was at a standstill,” says Frank Petter. “Technical control problems were the main issue with it.”

The Right Controller for the Hydropower System

“The controller in the system wouldn’t switch on, the control panel didn’t work, and we had no internal programs,” says Petter. As a result, the automation specialist in the GeP team looked around for a suitable new solution – and the CompactLogix™ controller from Rockwell Automation caught his eye. “It’s exactly the right controller for our purposes and offers the same functionality as large controllers,” he adds. The CompactLogix™ series handles safety, motion and drive elements, as well as discrete functions, with a single controller. It integrates programming software, control and I/O modules, helping to reduce development time along with commissioning and operating costs. As GeP found that the controller was also cost-effective, it decided to replace the old controller with a CompactLogix™ L1. “Another advantage was that the controller is already equipped with 16 inputs and outputs – exactly the same number as the previous one,” notes Frank Petter. “The Rockwell Automation controller’s dimensions were also slightly smaller, so we didn’t need to change anything in the existing wiring cabinet.” The team could simply fit the CompactLogix™ onto the existing top-hat rail and connect the corresponding I/Os. “We also used a decentralised Point I/O from Rockwell Automation, as we needed to wire some additional I/Os,” he adds. This modular I/O component is particularly suitable for industrial applications that require flexibility as well as low implementation and operating costs for the control system.

Safety Functions Are a Top Priority

Today, the CompactLogix™ controls both turbines in the hydropower system at the Neue Hütte museum. It keeps the water in the inflow tank at a constant level by using valves to supply the turbines with the right amount of water. Other functions controlled by the CompactLogix™ include the selection and interaction of the turbines. An unusual characteristic of the systems is that one of the turbines operates with 11kW power and the other with 30kW. The controller also ensures that the system connects to the electricity grid at the right frequency (synchronisation) to supply energy to it. However, the most important functions are related to safety. “If a fault occurs, the controller needs to power down the plant properly and make it safe,” explains Petter. “That includes stopping the water flow and opening the barrages – otherwise the system would be destroyed and the museum would become flooded.” The controller is equipped with 24V batteries to ensure operation even if there is a power cut. Power cuts can be dangerous – even for a plant running smoothly. One example of the controller’s safety functions is how it works during maintenance work on power lines, as Frank Petter explains: “If a technician is working on a power line connected to the electricity grid, the controller stops the outflow of power from the turbines. Safety functions are our top priority here!”

The entire plant is operated using a PanelView™ Plus 6 graphic terminal. This provides a graphical interface that allows the operator to view, monitor and control all status information. “We get a large number of signals from this system,” says Frank Petter. “That’s why visualisation is the most critical aspect of system control.” Especially as the plant can also be operated manually if desired. “When that happens, we need precise information about the system’s current status. The visualisation on a graphics display is a big advantage – we can detect any problems immediately on the overview screen and act quickly to resolve them. And if the operator needs more details, they’re available in the appropriate sub-images."

Faster Programming with Faceplates

Although Frank Petter had no prior knowledge of Rockwell Automation, he had no problem getting to grips quickly with the programming of the plant. “The documentation is very detailed, so I used that to familiarise myself with it.” He also found the faceplates helpful. “They’re pre-built visualisation templates used for various control disciplines,” explains Frank Petter. “Rockwell Automation updates them regularly; they facilitate programming and reduce development time.” GeP also signed a TechConnectSM contract with Rockwell Automation just in case Frank Petter needed any help. It includes real-time phone support from Rockwell Automation specialists, who answer questions on installation and configuration and help with error diagnosis and resolution.

Everything from One Source

“The Rockwell Automation product range really has everything I needed for this project,” concludes Frank Petter. “I don’t even need a different tool for programming, as there’s a consistent approach throughout the entire product range.” As the automation solutions are scalable, a small system can be expanded with no problem, and GeP is planning to extend the automation system with a Rockwell Automation PowerFlex AC drive. The company will use it to optimise settings for the turbines’ operating point, so that their speed can be adapted to the amount of water available, allowing them to produce more power.

The hydropower system at the Neue Hütte has been back in operation since the beginning of September 2013, producing energy that is fed into the grid. Profits from it are used for maintenance and other investments. The town benefits by having a “living” museum, which attracts a lot of visitors and makes the town a lively place to be. Some visitors participated in the creation of the museum many years ago or helped with the building work – and are now delighted with the result. Speaking to them, it becomes clear how happy they are that the hydropower system is back in operation and that they were able to experience it. “That also gives us some additional motivation and spurs us on to implement this type of project,” concludes Petter.

The results mentioned above are specific to this customer's use of Rockwell Automation products and services in conjunction with other products. Specific results may vary for other customers.

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