Reliable electricity distribution
Our first and foremost duty and goal is to distribute electricity in a reliable and secure way. A reliable electricity network guarantees the best customer experience. We actively improve our network with a long-term view, to be able to meet the requirements of our customers and the society, both now and in the future.
- In 2017, our focus was on the customer experience, mainly in terms of the reliability of supply.
- We installed over 6,000 kilometres of cables underground in order to protect our network from adverse weather conditions.
- We spent EUR 276,5 million on renovating and constructing our electricity network.
- We upgraded our contingency and emergency plans needed in case of network disturbances and exceptional circumstances.
- With the underground cabling carried out in connection with our network improvement programme, we were able to transfer over 45,000 Caruna customers to an electricity supply service that is more reliable than ever and meets all the reliability of supply requirements.
- Our reliability of supply rate was 99.98%.
Electricity network in numbers
Network maintenance and development
As Finland’s largest electricity distribution company, Caruna owns over 85,000 kilometres of electricity network. We plan, build and maintain our network to meet the current and future needs of our customers and society. We monitor our electricity network 24/7 and our contractors are on stand-by in our network areas, ready to carry out maintenance and repairs in the event of faults.
Case: Network maintenance and development
A helicopter takes off carrying the pilot, 3D laser sensors and a high resolution camera. During the flight, the sensors survey the terrain: data about the condition of the electricity network and the location of trees is transferred via the helicopter’s equipment to the inspector’s terminal.
You might think this sounds like some hypothetical situation in the future but it is a routine inspection of the electricity network. And thank goodness it is because without a high resolution camera and 3D laser, pinpointing faults would be considerably slower.
Although the majority of the network lies underground, overhead lines still have to be inspected regularly. Particular attention is paid to the trees growing near these lines because a gale or heavy snowfall could cause them to fall onto the line. This could then result in a power cut affecting thousands of homes.
“Regular inspections to check the condition of the lines are a part of Caruna’s programme to improve the electricity network’s reliability of operations. Aerial surveys play an important role in all our activities because they help us to direct our investments where they are most needed,” says Sauli Antila, Head of Network Development at Caruna.
With laser modelling it is possible to estimate the growth direction of the trees a decade from now, which helps to prevent faults and disturbances in electricity supply. Previously, inspections to check the condition of electricity networks was carried out through a visual examination of photographs. Now network planning is a lot quicker because the analysis of the pictures stored can be automated using the sensor data.
Helicopters are also used when thinning trees, although for safety reasons there is also an electrician on the ground. Many landowners may already have received a notice about tree thinning performed by helicopter. Often just the simple act of removing branches stretching across the electric lines is enough to prevent power cuts caused by storms.
Aerial surveys are often also carried out after a storm to find the fault locations in the network as quickly as possible and to prevent further faults. You will probably continue to see helicopters performing such tasks over the next few years, although there is already talk about utilising drones.
Caruna is running a ten-year network improvement programme, installing more cables underground to minimise weather damage. We are committed to meeting our statutory targets defined in the Electricity Market Act by 2028, when we will be able to restore power to our customers in a power cut within six hours in urban areas and within 36 hours in rural areas. We invest roughly EUR 200 million into our electricity network every year.
Goals for the security of supply defined in the Electricity Market Act
Our network improvement programme is guided, in addition to the target level of the security of supply outlined in the legislation, by the electricity network’s age profile and growth, mainly achieved through new network connections and advancements in the society’s basic infrastructure, among other things. The network constructed now must be able to serve the Finnish society for the next 40 to 50 years and reflect the relevant changes in the consumption and production of energy, such as the electrification of traffic and small-scale production of electricity.
Factors guiding our investments
We make the investments related to the reliability of supply in order of their customer impact, prioritising those that benefit our customers the most. The actions will first be targeted into areas with the greatest customer density and quantity of distributed electricity. In 2017, we continued to carry out more and more underground cabling work outside urban areas.
In 2017, we continued to carry out more and more underground cabling work outside urban areas.
We work on our electricity network in large geographical blocks, which allows us to optimise both the related purchases and the environmental and technical aspects of the work. Project planning is guided by life cycle costs: even though underground cabling is slightly more expensive at the construction stage compared to traditional overhead lines, its maintenance and repair costs are lower.
We also improve the reliability of electricity networks by various technical solutions. For instance, we are able to isolate faults in the electricity network and resume power supply to undamaged network sections faster, thanks to meshed networks and network automation. We also manage forest areas in close proximity to power lines.
Caruna’s Asset Management unit is in charge of managing the electricity network assets.
Electricity network improvement measures in 2017
In 2017, we continued to make extensive investments into improving the reliability of supply in all our network areas. Renovation of medium voltage networks remained the main focus of our network improvement projects.
In total, we constructed more than 6,000 kilometres worth of small and medium voltage cable networks. The cabling level of the entire electricity network was 45% by the end of 2017. With the underground cabling carried out in connection with our network improvement programme, we were able to transfer over 45,000 Caruna customers to an electricity supply service that is more reliable than ever and meets all the reliability of supply requirements.
Reliability of supply in 2017
Our electricity network was spared from exceptional storms in 2017. The greatest factors contributing to the lengthening of the average times expended on repairing faults in the network were Storm Kiira in Southern Finland in August and the snowstorm on 26th October 2017. Furthermore, the western parts of South West Finland were tested by a crown snow-load in December. Network improvements carried out from 2014 to 2017 decreased the impacts of weather on electricity supply. The level of our reliability of electricity supply remained the same as the year before, at 99.98%.
The level of our reliability of electricity supply remained the same as the year before, at 99.98%.
In 2017, the figure reflecting the frequency of supply interruptions, SAIFI (System Average Interruption Frequency Index), was 1.8. This means that, on average, customers were subjected to less than two supply interruptions during the year. The figure reflecting the total duration of power cuts per customer, SAIDI (System Average Interruption Duration Index), was 123 minutes during the year.
The key figures also take into account planned supply interruptions. The number of planned supply interruptions has increased because Caruna is running a major electricity network improvement programme, and the commissioning of new network sections results in planned supply interruptions to customers. We inform our customers of these interruptions in advance.
Preparedness for exceptional circumstances
Society is more dependent than ever on a reliable supply of electricity under all conditions. Interdependencies between critical electricity and IT networks and customers have been analysed, for instance, in a study by the National Emergency Supply Agency.
We strive to guarantee an electricity supply service that is as free as possible from disturbances. In case the supply of electricity is interrupted, Caruna, as the operator of the distribution network, is required to inform its customers and the authorities in charge of rescue operations without delay. Customers and the authorities must also be provided with an estimate of the extent and duration of the interruption. The authorities receive the information through the Critical Infrastructure Disruption Control Room Cooperative Group (Krivat in Finnish), a portal used by the authorities and infrastructure organisations critical for the security of supply.
The electricity interruptions map on our website offers our customers up-to-date information about supply interruptions and estimated repair times.
The electricity interruptions map on our website offers our customers up-to-date information about supply interruptions and estimated repair times. The number of customers affected by interruptions in Caruna’s electricity supply is also shown in the electricity outages map service of the Finnish Energy website. Our customers can also subscribe to the free alert service Caruna Sähkövahti that informs users of outages directly to their mobile phone or e-mail, whichever they prefer. We also give our customers advice on how to prepare for electricity supply interruptions.
Caruna has drawn up contingency and emergency plans for network interruptions and exceptional circumstances, as required by the Electricity Market Act. The contingency plan covers electricity network disturbances under normal conditions, such as power cuts caused by natural phenomena. The emergency plan, in turn, describes how to secure the reliability of electricity supply under emergency law conditions in case of serious external or internal threats. We continue to refine these plans and our practices on the basis of experience gained from disturbances and failures.
Preparedness for exceptional circumstances
The contingency and emergency plans required by the Electricity Market Act must be updated regularly. We submitted the most recent updates to our plans to the authorities in December 2017. We review our plans four times a year to ensure an appropriate level of continuity management. Caruna’s Network Operations unit is in charge of contingency and emergency plans. The Head of Security ensures the plans are up to date and appropriate reports are submitted to the authorities.
Caruna takes part in contingency and emergency organisation activities organised by the authorities, with the purpose of ensuring collaboration and readiness in all situations.
Security of supply
We are prepared to maintain our ability to supply electricity on the current level of reliability of supply even during a longer crisis.
As the largest distribution network operator in Finland, Caruna is considered a critical company for the security of supply. Security of supply means the ability to handle disturbances and crisis situations with a minimum amount of special arrangements and damage. We are prepared to maintain our ability to supply electricity on the current level of reliability of supply even during a longer crisis.
We took part in three energy security training events coordinated by the authorities in 2017. By investing in the reliability of our electricity network, we ensure the security and continuity of supply, particularly during disturbances caused by the climate.