Energy efficiency is still an underestimated cornerstone of the energy transition. This is surprising, given that efficiency gains not only conserve resources but also save energy and costs. Lutz Beyer, responsible for sales at the measurement technology and solutions provider PQ PLUS GmbH, and Thilo Schlesiger, team leader for operations at the distribution network operator REDINET Burgenland GmbH, explain the importance of measurement, analysis, and control at the electricity distribution grid level.
"et": Mr. Schlesiger, as a distribution system operator, you have to manage the integration of flexible generators and new loads. How did you approach the digitalization of your grid?
Schlesiger: As a small grid operator, we operate a medium-voltage grid with 131 of our own local grid stations, which we want and must digitize in accordance with Section 14a of the Energy Industry Act (EnWG). About three years ago, we decided to actively implement this topic – on the hardware side with our partner PQ PLUS, PS Insight for data analysis, and the GridCal system for optimized grid analysis and simulation. We chose a retrofit solution for our systems. It was also important that the interplay of measurement technology and software provided us with timely measurement results that didn't have to be integrated into any other systems. In other words, we wanted to gain reliable insight into our grid as quickly as possible without having to invest a great deal of IT effort in the background. The package you chose was the most suitable option for us.
Lutz Beyer, Sales, PQ PLUS GmbH, and Thilo Schlesiger, Team Leader Operations, REDINET Burgenland GmbH, provide insights into the practical rollout and the potential of intelligent metering technology for the distribution network
"et": What should be considered during the rollout?
Schlesiger: This question has occupied us intensively. The obvious approach seems to initially only measure the points where one knows there might be problems in the grid. But from our experience, I can say that this approach is misleading. A coherent overall picture can only be obtained by mapping all stations together. We have a tightly meshed medium-voltage grid, and this extends into the low-voltage grid. By measuring only one of five stations and generalizing across the entire grid structure, one cannot gain comprehensive insights that allow for informed decisions.
"et": Mr. Beyer, both small and large distribution system operators will face the challenge of gaining an overall picture. How can you quickly provide tailored solutions?
Beyer: Our approach is to offer customers options that are directly applicable. We developed our measurement technology and software solution with a major distribution grid operator – Stadtwerke Krefeld – and PS Insight. The requirement at the time was a rollable standard that had to fit approximately 1,000 grid stations and be so easy to install that a single electrician could perform the work. The measurement technology kits themselves are modular and accommodate different designs. We cover approximately 95% of all configurations we see at our customers using standards. However, we also fulfill special specifications – for example, when special corrosion protection is required in coastal locations due to salt spray. In general, we focus on robustness. The electronics can withstand temperatures from -25 to +70°C. As overvoltage problems are becoming increasingly serious, overvoltage category IV is the norm for us. Our customer experience shows that investing in digitalization solutions with innovative measurement technology in grid operations and other system effects pays for itself within five years.
"The digitalization of distribution grids is becoming an indispensable bridging technology on the path to highly automated, efficient grid operation. GridCal offers the linking of infrastructure and consumption data, and thus possible grid calculations, as a new tool for grid operation. This enables strategic asset management."
Dipl.-Ing. Lutz Beyer, Sales, PQ PLUS GmbH, Langensendelbach
"et": Infrastructure expansion is struggling with shortages, Mr. Schlesiger?
Schlesiger: That's true, so it's an advantage that the solution can be implemented even with a relatively small staffing level. The retrofit version can be installed using the plug-and-play method. Thanks to the component design with intelligent computing technology in the on-site programmable logic controller (PLC), a local grid substation can be visible online in the monitoring system within two to three hours.
"et": Does the substation have to be temporarily taken out of service for installation?
Beyer: The existing installation is simply built over. Nothing needs to be shut down. An electrician qualified to work under voltage can easily implement this. The components – measuring device, log and power quality recording, as well as PLC automation – are linked together. Data transmission is provided by a standard LTE wireless network router with secure VPN transmission or, if available, a fiber optic connection. Everything is simply pre-configured: The hardware is installed and the technology is connected. It works immediately when the power is switched on. To communicate, only an IP address needs to be configured. For the medium-voltage transformers, the location of the station is determined using a multi-step form.
Schlesiger: The preparatory steps before installation are minimal. "Only" the digital twin needs to be created. This means that the data from the local network substation – building data, transformer data, transformer tap-setting, medium-voltage system, low-voltage structure, including the feeder designations – must be created in the Gridcal node so that they are available as a digital twin.
Immediate benefit: Monitoring of limit values for current and voltage values
"et": How do you use the solution in practice?
Schlesiger: We collect our measurement data 24/7, which we store via edge computing in our grid stations on the physical servers installed there. From there, we then receive targeted notifications when voltage or current limit values are exceeded, which we use to guide our actions.
"et": Does that mean you are initially deliberately keeping the amount of data that accumulates in your control center small?
Schlesiger: Large distribution system operators begin their digitalization projects with the requirement to first set up an IT infrastructure, including the cloud, and to consider the question of system integration with the systems to be used. As a small distribution system operator, however, we wanted to avoid high data fluctuation and get into operations quickly. That's why we work directly with targeted information, such as current and voltage values, which the GridCal system provides us when we reach critical limits. As Mr. Beyer already mentioned, the system is modular. All the co-systems I manage – such as ERP systems, GIS systems, and intelligent metering systems, etc. – can be integrated and complement the system. For a small grid operator without an extensive IT infrastructure, such as ours, this has the advantage of being able to immediately derive added value from measured values and data. The use of all data from the GridCal system, including the connection to the aforementioned co-systems, is already actively taking place alongside the rollout. The second step for us involves mapping graphic data from the GIS system for grid modeling. This means that the calculation and simulation of the distribution grid takes place directly in the GridCal operator.
In PQ PLUS's GridCal system, the grid station and the local grid form a single cell that operates independently of the central office. At the central office, the GridCal operator compiles and manages the essential information from the individual grid cells.
"It was important to us to approach the digitalization of the distribution grid as simply as possible. This can only be achieved with a simple, manageable, and user-friendly IT infrastructure. For us, simplicity in the connection, coupled with reliable hardware, is important."
Thilo Schlesiger, Team Leader of Operations at the distribution network operator REDINET Burgenland GmbH, Zeitz
"et": Will monitoring and control then be handled via the digital twin at the central office?
Schlesiger: The digital twin is located in the GridCal node – i.e., the local grid substation. It records all measured values via the measuring transformers and delivers them directly to the PLC. Each installed node can be accessed separately, and all measurement data is stored there 24/7. A central software package – the GridCal Operator – consolidates all GridCal nodes for access. It serves as a control center." The GridCal operator handles the handling and direct access to all local grid stations. Visualization and intervention only occur when a limit violation is reported to me. Furthermore, the software also calculates the grid. Software modules for calculating connection requests and grid simulation are also available.
"et": What insights have you gained so far?
Schlesiger: We have invested heavily in our power grids since 1990 – in medium and low voltage, as well as in the grid stations. Politicians and the Federal Network Agency always emphasize the importance of monitoring in connection with the expansion of electromobility and PV system capacity. In our experience, however, current carrying capacity poses fewer problems. We see critical limits primarily in maintaining the voltage range according to EN 50160. Here's a current example from our medium-voltage switchgear. We are a grid operator without our own substation. Our upstream grid operator naturally has to make voltage adjustments at the 110 kV transformers in the substation to keep frequencies stable. At the beginning of our measurements, we received reports that there was a tendency for voltage limit violations in our low-voltage feeders at the distribution substations. We were able to quickly resolve the problem by tapping the distribution transformer. This ensures that the feeders, which are connected to a large number of PV feeders, remain within the desired voltage parameters without causing the inverters in the customer systems to shut down.
"et": What would have happened earlier?
Schlesiger: The PV system operator would have contacted us because their inverter was constantly failing. Then a power quality measurement would have been installed on-site, and in the worst-case scenario, a concrete result would have been determined within three weeks, enabling us to implement measures in the grid. Thanks to our automated measurement data and visualization, we were able to act ad hoc in this case and adjust the voltage accordingly, allowing the PV system operator to continue feeding in electricity.
More transparency creates flexibility
"et": Do measurements and evaluations also help us make more informed investment decisions?
Beyer: With a good basic data collection concept, many simultaneity considerations can be put aside. If you see that there is only a brief outlier at one point once a year, then this can be limited. Measurement provides the certainty that you don't have to immediately strengthen your grid. Data is the basis for sensible management and grid planning.
"et": The next step is to also manage the future with an innovative, intelligent distribution grid. Is that already possible?
Schlesiger: The basic requirement is that I can identify bottlenecks in the system. We already have this possible thanks to the measurement data. And the GridCal system, with its precise outgoing recordings, can communicate with the intelligent metering systems and the downstream control units. This means that the GridCal system, via the gateway administrator, issues the command to limit the power to, for example, 4.2 kW per connected user. Here, too, a functioning and functional basic system is a prerequisite. Only comprehensive monitoring allows me to regulate without discrimination.
The GridCal system has a modular design. Available options range from large cabinets with expansion reserves for accumulators to compact boxes for smaller spaces and digital strips for compact stations.
"et": Where do you already see clear cost-relevant advantages?
Schlesiger: The comprehensive measurement data acquisition and the associated ability to quickly evaluate it provide us with decisive advantages in our day-to-day operations and allow us to implement targeted, cost-optimized grid expansion for the energy transition.
Beyer: This is where continuous power quality measurement comes in. The UMD measuring devices measure, monitor, and report violations of standards. In the past, highly specialized personnel were required to identify problems, with measures only being derived from snapshots. Power quality measurement and monitoring are always running in our solution. This means that the user detects changes before they become serious, as they can see them immediately and react accordingly. They have insight into grid behavior and can learn how their grid behaves. The software helps them avoid flying blind.
"et": Transparency helps uncover errors and save money...
Beyer: Here's an extreme example: We were once called to a grid operator where an industrial consumer had determined, using their internal metering devices, that their billed electricity didn't match their consumption. We then installed our metering technology and were able to immediately confirm the mismatch. The result: The grid operator had incorrectly set the transformer meter and had only been billing half the amount for years. The damage, which ran into the millions, would have been detected much earlier with innovative metering technology on their side.
Data sovereignty in focus
"et": Speaking of damage, the question of security is obvious. Mr. Beyer, how does your solution handle data security?
Beyer: With our system, everything is logged decentrally on a proprietary system in the local network substation and then – importantly – transferred to their own infrastructure. Many of our customers manage their own data storage and use the data center of their choice. This means that we generally don't offer a cloud solution, and therefore don't offer a subscription model where each new data stream from a measurement point requires payment. In my opinion, every customer should be able to access their own data free of charge and remain in control of their data history. Only then will they be able to migrate data at any time in the future without losing any knowledge. This is a strategic approach we recommend to our customers: not putting data into the hands of strangers. We are currently seeing that, given the changing global political situation, it is no longer a given that IT service providers offering large-scale cloud services are immune from political influence – keyword USA.
"et": Mr. Beyer, Mr. Schlesiger, thank you for the interesting conversation!
Efficient energy management technology also for industrial consumers
Companies with a total annual energy consumption of more than 2.5 GW are required to implement an energy management system (EnMS). PQ PLUS's experience confirms that a primary measurement alone does not reveal any potential problems within the company. Only with the retrofitting of metering and measurement technology does it often become clear where a company needs to improve its physical design. For example, many companies today use a large amount of power electronics. These can disrupt frequency converters through loads and leakage currents. Modern measurement technology helps identify risk scenarios early on. In addition to the traditional energy management offered by PQ PLUS measurement technology in conjunction with its software, it can also provide information that supports strategic corporate decisions. Modern measurement technology not only monitors energy flows but also displays other media such as water usage or tank consumption. This is particularly relevant when comparing systems or system components. If deviations occur, the magnitude of the deviations and consumption levels becomes relevant for deciding, for example, on a retrofit, system replacement, or decommissioning. Such strategic decisions are only possible when a cost-benefit analysis can be conducted based on concrete data.
