The Gräper Group has equipped the supply stations in its own factory with the PQ Plus energy monitoring system. The experiences will flow into our own station solutions for industrial microgrids.
Image: Beton- und Energietechnik Heinrich Gräper GmbH & Co. KG
What do microgrids have to look like so that they are able to ideally coordinate energy production, storage and consumption? In order to clarify this question, transparency about energy flows is a mandatory requirement - right down to the level of individual, selected production facilities. In a joint project, the Gräper Group is testing the systematic recording and analysis of energy flows at its Ahlhorn factory together with PQ Plus. In the long term, the Lower Saxony station manufacturer plans to transfer the findings from the pilot project to industrial microgrids and integrate them into its transformer station technology according to individual customer requirements.
80 measuring points are enough
At the end of 2023, PQ Plus started integrating the new energy management system into Gräper's factory energy network. “Since it is not a public network, we wanted to record all relevant network sizes in the first part of the pilot project. For this purpose, we installed a total of 80 measuring points in the various in-house low-voltage distribution systems,” reports Andreas Bleyer, technical sales representative at PQ Plus. The UMD 98 and UMD 913 panel-mounted measuring devices were integrated on both the low-voltage and medium-voltage sides. The MMI 12 modules for the busbars were installed at several points in order to monitor strategically important low-voltage outlets. With these measures, the consumption and load curves of selected production systems - for example cooling units, mixing systems for concrete - as well as the feed-in of the two in-house PV systems are precisely monitored. “In addition, a few outlets to check the energy flows in the administration buildings were equipped with our measuring systems. Some measuring points that record heat and water quantities were also included in the measuring architecture,” adds Andreas Bleyer.
The assembly and commissioning of the devices was carried out by Gräper's assembly teams, supported by the technical know-how of PQ Plus: In the retrofit, the measurements were retrofitted using small signal converters. This meant that installation could be carried out without switching off parts of the system
be realized.
The energy monitoring hardware UMD 98 and UMD 913 register disruptions or changes in the factory power network and seamlessly record all parameters of the electrical energy supply.
(Image: PQ Plus GmbH)
Real-time energy data
After installing the hardware components, the system was parameterized in collaboration with PQ PLUS and integrated directly into the measurement technology provider's separate energy management network ENVIS Web. The software enables users to: access the energy data access in real time. For this purpose, ENVIS visualizes the recorded measurement data from files or SQL databases. In addition, the ENVIS energy management system stores and visualizes all measured values for network quality and energy efficiency. This functionality ensures that no important measured values are lost even in the event of short-term power failures. This means that special incidents, such as voltage fluctuations, network interruptions and harmonic assessment, can be clearly identified and assigned in terms of time and location.
The visualization of measured values in the energy management software ENVIS shows the scaled energy balance of individual production equipment or hall sections.
(Image: Beton- und Energietechnik Heinrich Gräper GmbH & Co. KG)
On the trail of the defective cooling unit
After the system was successfully implemented, the first significant results were already achieved. By visualizing the measured values, it became clear when and how much energy was needed at the location. The experts immediately noticed a relatively high base load in the factory, which remained constant throughout the entire day. This gives those responsible for the company a first point of contact that they can optimize energetically. The energy monitoring system is also able to detect significant load peaks at individual production facilities. “Thanks to the detailed measurement data, Gräper was able to identify the leak in a cooling unit. In this case, the monitoring system also recorded unusual power peaks on the weekend that were above the base load. After closer analysis, the error was narrowed down to the faulty cooling unit,” explains Andreas Bleyer.
Thanks to the knowledge gained from the load flow analysis, Gräper can now specifically look for savings potential and, in the future, control some consumers - e.g. the charging infrastructure or both of the factory's own PV systems - in such a way that load peaks in the factory network are reduced and the network utilization is stabilized. The company also aims to reduce its own CO2 emissions through more efficient use of energy flows.
Thought further
The Lower Saxony concrete and energy technology manufacturer consciously chose the measuring systems from PQ Plus because they are well suited for the new construction and retrofitting of low-voltage distribution systems. “The flexible design of the sensors allows the system to be adapted for other energy sources such as natural gas or hydrogen in the future. This opens up new business areas for Gräper. Another advantage is that the measurement technology can temporarily store the collected data and retrieve it at a later point in time. “Through intelligent load management and precise visualization of energy flows, industrial customers can optimize the use of energy in their own industrial network and ultimately reduce costs,” summarizes Andreas Bleyer. The flexibility of the system ensures that it can be used for different structures. The energy management system, which is currently in operation at the Ahlhorn factory, will be used at another five GRÄPER Group locations in the future. In the future, Gräper wants to incorporate the knowledge gained from the project into its own product and service portfolio in order to move from the current prototype phase to finished end products in the next step.
