Real-Time Power Flow Calculation Supports Elenia in Green Transition Challenges
At Elenia, the second largest distribution system operator (DSO) in Finland, the green transition is already well underway. In addition to consumption, a significant amount of power flows from Elenia's grid towards the transmission grid. As the share of renewable energy increases, a new, advanced operational support system is needed to manage the electricity system. The cornerstone of this system is Trimble's reliable and high-performance, real-time power flow calculation, which combines SCADA and network data with data from smart meters, and which Elenia has been involved in developing.
Power flow calculation supports the DSO's operational work by providing more detailed situational awareness of the electrical state of the grid. Alarms triggered by calculation results that fall outside the DSO's defined limits enable faster response to problems. This helps prevent outages and grid damage that would occur in a changing energy landscape, driven by the energy transition, if operational support solutions did not evolve accordingly.
Teemu Suvela, Control Center Manager at Elenia, describes the grid phenomena of the renewed electricity system as so complex and challenging that humans can no longer calculate and analyse them in a timely manner.
"Considering distributed generation and battery storage in real-time calculations and all analyses is crucial to being able to manage the grid of the future at all. Elenia's electricity grid already has 1,300 megawatts of wind power connected, and there are approximately 17,000 production sites already connected," he says.
Extremely High-Performance Real-Time Calculation
The goal of the power flow calculation development project, which combines SCADA and network data, was to achieve reliable and high-performance real-time calculation and an optimised network model for this purpose. The project also aimed to deliver useful results to support operational work on the production side of the DMS (Distribution Management System).
The project has been a significant step towards a more advanced and efficient operational support system. Real-time power flow calculation of radially fed medium- and low-voltage networks provides situational awareness that is needed to manage complex grids. So how is this situational awareness created?
The real-time model of the power flow calculation uses measurement data from the SCADA system and smart meters. Suvela explains that the information coming from the distribution network is truly real-time: “From these new smart meters, of which we have already installed over 200,000, a five-minute time series arrives with a delay of about 10–20 minutes.”
The operational support system analyses incoming data, and if any calculation result is outside of Elenia's predefined permissible limits, the system issues an alarm. “From an operational point of view, this is a big deal. Calculations are constantly running in the background in cycles, and in particular, prioritisation also takes place there. In other words, wherever a switching change is made, that starting point jumps to the top of the calculation. We always have the best possible information available on switching changes,” explains Teemu Suvela.
Even if there are no changes in switching, the real-time situational picture is still beneficial. Suvela points out that the grid load can change much faster than anticipated, even without any switching changes.
“For example, if someone installs solar panels or charging stations for electric cars on one street, their neighbours might suddenly do the same. In other words, the cycle of how grid generation or loads can change is much faster. It is good to have real-time visibility into load capacity so that overloads do not come as a surprise in subsequent reviews,” says Suvela.
Suvela says that real-time power flow calculation works for Elenia’s 440,000 customers and certainly for much larger volumes. “We achieved extremely high-performance calculation. With our network size, one feeder is calculated in fractions of a second, and our entire network – over a thousand MV feeders – is calculated in less than ten minutes,” says Suvela.
“The calculation model has been implemented so well that it uses the best available load and voltage information. Even if we didn't have new smart meters everywhere and only hourly data from meters was available, or if some SCADA measurement happened to be unavailable at some point, the calculation would still work and provide us with results,” he continues.
The Tipping Point of Reliability
Extreme performance is of no comparable benefit if the user of the system cannot trust the results they receive.
“Even though the system itself might work 80 or 90 percent of the time, and only every fifth or tenth time there is information that you might have to double-check, this can bring reliability down to zero from the user’s perspective. The user is unable to abandon old ways of working and has to unnecessarily question the result too often or carry out laborious checks to find out what is really behind the result,” Suvela explains.
He emphasizes that the reliability of the results must reach 98–99 percent. This way, unreliable results are rare enough that control room operations can begin to abandon old operating models. “We can start to trust that only rarely will we encounter cases that we have to dig through,” says Suvela.
Abandoning Old Ways of Thinking
As a result of the project, SCADA measurement data has now been brought together with network data for the first time. Teemu Suvela says he sees achievable benefits in combining and comparing network data and SCADA measurements, even without any further analysis or calculation. For example, the current measurement of a medium-voltage source can be compared to the rating of the source's current transformers and many other factors when one abandons old ways of thinking.
“The guiding principle has been that we have a measurement in SCADA and with it a static alarm limit. This is not the case,” he says.
“We have a network, it is designed in a certain way, and there are certain types of components there that have certain limits. Measurements must be compared to the limits of these components, which in practice form the alarm limits. In this way, as the network documentation is updated, the alarm limits are also updated automatically as the component data is updated, and we don't have to maintain static alarm limits for individual measurements,” Suvela continues.
Documentation Quality and Up-to-Dateness are Important
The objectives of the project – reliable and high-performance real-time calculation, an optimised network model for this purpose, and results to support operational work on the production side of the operational support system – were achieved. So, what lessons were learned?
A good decision was to start developing the power flow calculation at Elenia alongside the production environment. This made it possible to develop safely and agilely without endangering the production system. According to Suvela, Trimble was able to bring parts to testing quickly without impacting production.
Suvela emphasizes that the quality of network data is very important, and it is important to ensure that documentation is up-to-date. “We did make some observations about documentation that needed to be corrected and about what kind of continuous checks should be put in place for validating the documentation of the network information system. In other words, if errors are found in the documentation, they should be corrected quickly. You can’t calculate with real-time measurement data if the network documentation isn't real-time,” Suvela emphasizes.
From Real-Time Calculation to Predictions
Power flow calculation serves as an example of a way to manage the grid based on real-time information and analytics, but very soon we will be at a point where real-time is no longer enough, and predictability and flexibility are needed. Advanced operational support systems must provide even more accurate information about the state of the network, the operating environment, and potential future disruptions.
“Capacity maps and predictability are at the heart of it when we think about a grid that has historically been built to be strong but is now facing new challenges with distributed generation,” Teemu Suvela explains. For this reason, it is essential that the operational support system can provide more accurate information about exceptional switching situations and anticipate potential problems in advance.
According to Suvela, in the future, data obtained through open interfaces could also be used to make predictions, such as sunshine and wind data provided by the Finnish Meteorological Institute and wind power forecasts from Fingrid. With data brought in from outside the system, the system would be able to recognise exceptional situations even better and would be able to tell in advance whether production needs to be restricted.
Help with Managing Flexibility Needs and Related Communication
In the future, Elenia and other DSOs must be able to utilise flexibility even better and communicate flexibility needs with the market and flexibility platforms. The role of the ADMS system is emphasized in this context, as it enables the management of capacity and flexibility needs, as well as communication with various actors.
“DSOs need to develop flexibility in cooperation with authorities and the market. The operational support system of the future must be tightly integrated with platforms related to flexibility,” Suvela emphasizes.
Technology is Evolving – User being on the drivers seat
The intelligent power flow calculation developed in collaboration between Elenia and Trimble provides critical support in today’s increasingly complex energy environment. It has created a solid foundation for the operational support system of the future, which is capable of responding to the challenges posed by the green transition. However, development must remain user-centric to ensure that new solutions serve real needs and that users are involved in the change.
“It is important to listen to user feedback and develop the system so that it meets practical needs and makes grid management more efficient and reliable,” Suvela continues. He emphasizes that the operational support systems of the future must be able to handle large amounts of data and provide real-time, predictive analytics that supports decision-making in complex network conditions.
As the green transition progresses and distributed energy generation increases, DSOs like Elenia are facing growing challenges. Efficient and intelligent operational support systems, such as ADMS, are key to ensuring the sustainability, reliability and flexibility of the electricity grid.
Suvela also highlights the importance of continuous development: “Technology is evolving rapidly, and we need to keep pace with this development so that we can take advantage of new opportunities in grid management and improve our services to customers.”
What Did We Gain from the Collaboration Project?
The collaboration between Elenia and Trimble has created the basis for advanced power flow calculation that supports the DSO in the challenges of the green transition. The operational support systems of the future must be flexible, predictive and able to integrate into the wider energy market and flexibility solutions. User-centric development and open collaboration between different actors are key factors in aiming to build a sustainable and reliable electricity grid for the future. And this is exactly the kind of system that was created as a result of the project.
Elenia's Control Center Manager Teemu Suvela gave a presentation titled 'Implementation, Experiences, and Opportunities of Real-Time Calculation' at Trimble's Suunta24 event in April. This article is based on Suvela's presentation.
