Ellevio is the second largest electricity DSO, in Sweden in terms of customers, representing approximately 17.5 per cent of the market with 962,000 customers spread across Mid-Sweden, the West Coast, and the Stockholm area.
Like many other network operators, Ellevio are facing the challenge of maintaining a stable, flexible, and reliable grid whilst integrating a greater percentage of renewable energy and meeting rising and evolving customer demands. To meet these, Ellevio have embarked on an ambitious digitisation project called Vision 2030. The sentiments behind Ellevio’s innovative Vision 2030 project is simple. Reduce the number of power cuts by half and ensure that those that do occur only last half as long. Mark Venables spoke to several of the people responsible for the project to discover its progress.
Electricity is playing an increasingly important role in society with expectations that it will always be available. For electricity network companies like Ellevio, it is all about meeting expectations. To achieve this, it is increasingly important to predict errors in advance, but if unwanted power outages still occur, network operators should act faster, communicate better, and fix the faults faster. The solution lies in digitalisation.
“We will move from a manual approach to a system that has increased automation – and the tool is digitalisation,” Stephan Stålered, project manager for the future electricity grid at Ellevio, says. “Our belief is that in this way we get the right focus on the outages and can reduce and shorten them for our customers.”
A paradigm shift
Stålered describes it as a paradigm shift for Ellevio where they go from reacting to faults to creating a smart grid that both sees the faults before they appear and that after they occur can fix them faster. He points to underground powerlines as an example. For many years, Ellevio has weatherproofed its network by replacing exposed overhead lines with underground cables. The result has significantly decreased power cuts. Initially that was a solution but now, as the cables age, faults begin to appear and underground cables are harder to both troubleshoot and fix than an overhead line.
“We need to provide our power grid with smartness to handle the cables, but also our overhead lines,” Stålered adds. “Our entire power grid needs to be smarter. Our electricity network is a database structure with lots of measuring points and no matter where they are in the grid, they are connected. By taking advantage of this information we can build up a database. This will allow us to identify if something is about to break. And if the fault still occurs, we have accurate information that allows us to locate and fix the fault a lot quicker.”
One technology that Ellevio will invest in is remote control of the network. Another technology is dynamic capacity management where a line’s transmission potential is mapped. For both technologies, pilot projects are under way.
Ellevio is also about to start replacing its customers’ electricity meters; these smart meters will provide information about the network’s voltage. Increased digitalisation also delivers the opportunity to provide even more customised information about events such as interruptions in delivery.
“Better information does not reduce the fact that the customer has an interruption, but a customer with us should simply get real-time information about why they are not getting electricity and how the repair work goes,” Stålered adds. “This is also an important part of our vision. We know from experience and surveys that downtime information is one of our most important communication channels with customers.”
Ellevio is now investing in digital remote control that will make electricity supplies even safer. When customers are hit by power cuts, the new technology will make troubleshooting much faster than today. “Our driving force is to minimise downtime for our customers,” Henrik Rinnemo, technical specialist at Ellevio, says.
There are numerous external reasons for power outages from a tree falling onto an overhead wire to a workman digging up a cable, but whatever the reason it needs to be rectified as quickly as possible. The first step is to reduce the risk of the electricity grid being exposed to events that result in power cuts at all and if they do occur, remedy them as quickly as possible. “It is a big difference for a customer to be without electricity for an hour compared to a few minutes or just a few seconds,” Rinnemo adds.
Ellevio is taking a digital approach to reduce downtime. A pilot project in Värmland, on a network that has traditionally been prone to interruptions, combines digital and traditional technology to shorten the downtime. “Previously, when an outage occurred, we manually determined where the fault was, electricians were sent into the field and step by step the grid was checked, and in stages the power was released to the customers,” Rinnemo explains. “Now computers are helping to produce a lot of information about the network so that our operations centre can draw conclusions and act much faster.
Dial in the error
In addition to a control system in the pilot there are modems, sensors and electric motors installed in the network stations. In the pilot project, this technology is connected to a switch that cuts the power very quickly when something goes wrong. This means that customers connected to the mains before the switch will not experience any interruption at all. Together with so-called power sensors and remotely controlled disconnectors in other locations in the network, the extent of the fault can be reduced, and it is easier to locate.
“You could say that we now have eyes in the network, which means that the fault can be repaired remotely by an operator at the operations centre and get the electricity back to our customers instead of us having to send out electrical fitters for troubleshooting,” Rinnemo says. “We can save a lot of time.”
More steps to come
The investment is an important part of developing Ellevio’s smart grid. The next step in the automation staircase is that an operator at the operations centre does not have to intervene when an interruption occurs but the operating system handles this autonomously. Looking further ahead, Rinnemo can foresee digitalisation taking another step towards autonomous solutions. “Then the computers in the different network stations can talk to each other locally, and when an error occurs, the computers themselves fix it so that the electricity is diverted,” he explains. “In the longer term, in some network areas this can happen within milliseconds, customers will not even notice the outage.”
With the pilot project in Värmland successfully concluded, Ellevio will begin the rollout of the technology later this year with the plan to equip 1000’s of network stations.
Measuring for more wind
Ellevio is also testing advanced measurement technology to enable them to put more electricity into the grid with the aim of bringing more renewable energy into the electricity system and increasing the security of transmission.
The need for increased capacity in the transmission is being driven by the desire to add more wind power to the network. Often this involves additional grid infrastructure so Ellevio is looking for alternative solutions. “There is spare capacity in our network today,” Erik Lejerskog, technical specialist at Ellevio says. “By using advanced measurement technology, we get a lot of information about the management and thereby can determine how much of the pipeline is not utilised and can then increase the transmission of electricity in the pipeline.”
The technology that Ellevio is now testing in a pilot project is called dynamic loadability. Measuring instruments are placed both on and next to the line to measure a variety of factors that affect the transmission characteristics. These are weather conditions such as wind strength, temperature, and the sun’s radiation – but also about how high the line hangs above the ground, whether there are any vibrations or whether the line is stretched in any way. The data collected provides information about how the network can be managed and whether it can handle an increased load.
“Building a new network system requires a large investment and takes a long time,” Lejerskog adds. “This is a technology that we can quickly get in place and effectively increase the loading. We have many wind power operators who want to join our network, so the technology is important for increasing the renewable energy in the electricity system.”
The network where Ellevio is testing the technology is a perfect example. The system runs between Glava and Värmskog in Värmland where there is a growing demand for connection from wind farms. This network is also important for exports and imports to Norway and this innovation increases the security of supply. Although the project is ongoing there are indications that the capacity of the current network can increase by about 20 per cent during the winter period.
“Exactly how we will use the technology will be decided when the test results are fully evaluated,” Lejerskog concludes, “But I absolutely believe that this will be an important part of how we use our electricity networks in the future in a more efficient and optimal way. All the information and data we can get about our network allows us to make better decisions and increase delivery reliability for customers. I also see greater potential with similar technology that could be used to collect more data from powerlines and becomes a tool for managing the capacity shortage in Stockholm.”
POWER GRID DISTRIBUTION
Security of supply means that electricity is transmitted to electricity users without interruption. According to the Electricity Act, a power failure may not exceed 24 hours. The concepts SAIDI and SAIFI are used to measure the power outages. SAIDI shows average downtime in minutes per customer per year. SAIFI shows the average number of interruptions per customer per year.
According to the latest full-year statistics from the Swedish Energy Market Inspectorate (2018), SAIDI in the Swedish electricity network amounted to 97 minutes and this corresponds to an availability of 99.981 per cent. SAIFI was 1.49 outages per customer.