New infrastructure projects and maintenance
Investment in new grid infrastructure projects in 2015 amounted to around ISK 3.7 million, which is similar to the preceding year’s investment costs. The large majority of these projects concerned grid renewal or strengthening, while others pertained to the construction of new connections for consumers.
The year’s largest individual projects concerned the installation of underground cables. Maintenance projects also took up considerable time. Extensive new infrastructure projects were prepared during the year, with investment in such projects in 2016 expected to be triple that of 2015, or about ISK 11 billion..
Connection for United Silicon
In 2015, we worked on the construction of transmission infrastructure for the connection of the United Silicon plant under construction at Helguvík in south-west Iceland. A new breaker was installed at the Fitjar substation, a 9km long 132 kV underground cable was laid between Fitjar and Helguvík and a new substation was constructed at Helguvík. These works were completed at the beginning of 2016.
Substation at Akranes
In co-operation with the multi-utility company Veitur, we worked in the construction of a new substation in the town of Akranes, west Iceland, which is scheduled for completion in the first half of 2016. Located in the industrial district in the west part of the town, the new substation will replace an old substation located in a designated residential area.
The installation of a new 28km long 66 kV underground cable connection between the towns of Selfoss and Þorlákshöfn in the south of Iceland commenced during the year and is scheduled for completion in the first half of 2016. We also worked on modifications to the substations at these towns. The new Selfoss Line 3 will improve the security of supply for the towns of Hveragerði, Þorlákshöfn and Selfoss.
Hella Line 2
In the summer of 2015, a new 66 kV, 13km long underground cable was laid between the towns of Hella and Hvolsvöllur in southern Iceland. Once the cable had been brought into service in September, the overhead line was demolished. It was one of the oldest lines of the entire grid, having been installed in 1948.
Modifications to the Sigalda substation
To increase transmission capacity via the Inter-Regional Transmission Network, we completed modifications to the substation at Sigalda during the year. With a new additional breaker and modifications to the high-voltage connections, the substation’s operation can now be split up to react to disturbances without any curtailments or supply interruptions experienced by customers. These improvements are primarily a temporary measure in response to the challenges of operating the Inter-Regional Transmission Network at levels exceeding stability limits for a large part of the year.
Transmission capacity of Sigalda Line 3 doubled
In the autumn, we completed the strengthening of the Sigalda Line 3, a 37km long 220 kV line between Sigalda and Búrfell installed in 1975 in connection with the construction of the Sigalda Power Station. Conductors and insulator chains were replaced and new transmission towers were constructed next to the Sigalda Power Station. This doubled the line’s transmission capacity for only about one-third of the cost of constructing a new one.
Construction works on the Snæfellsnes peninsula
Earthworks for the construction of a new substation at the town of Grundarfjörður in west Iceland began in the second half of 2015. The substation’s construction is scheduled for completion in early 2017. It needs to be expanded to accommodate the planned installation of a new 66 kV underground cable between Grundarfjörður and the town of Ólafsvík in 2017. Since the town’s limits now extend to the substation, enlargement of the substation at its current location was found unfeasible, so the decision was made to construct a new one. The construction of a new substation at Ólafsvík is also being prepared.
Purchase of reserve transformer
During the year, we finalised the purchase of a reserve transformer (132/66/32 kV) to replace transformers in the Inter-Regional Transmission Network and in other parts of the grid. In various locations around the country, delivery to customers is dependent on transmission through a single transformer. Having a reserve transformer provides a major boost to security of supply, since a fault in a transformer can take a long time to repair. The reserve transformer arrived in Iceland at the beginning of 2016.
Strengthening of the Hrauneyjafoss Line 1
The Hrauneyjafoss Line 1 was strengthened during the year by modifying a number of transmission towers and replacing insulator chains. Strengthening the line and increasing its transmission capacity in a section between Langalda and Sultartangi became a pressing issue after the Búðarháls Line 1 was connected to the Hrauneyjafoss Line 1 at Langalda.
Strengthening of cable ends
There are a number of bottlenecks in the grid where short underground cables extending from a substation to the first tower of an overhead line have significantly lower transmission capacity than the overhead line to which they connect. The decision has been made to replace these underground cables with higher-capacity ones. We worked on the design and preparations for this project in 2015. The cables have been purchased and shipped to Iceland. The first milestone, the installation of new cables at the Eskifjörður substation, commenced at year-end 2015, with other milestones to follow in 2016.
Sandskeið Line 1 and modifications in Hafnarfjörður
In the summer of 2015, we reached an agreement with the Municipality of Hafnarfjörður and the inhabitants of its Vellir district to make modifications to a part of the transmission network within the municipality. The agreement enables the demolition of the Hamranes Lines 1 and 2 and the removal from inhabited areas of the ÍSAL Lines 1 and 2, which extend from the Hamranes substation to the aluminium plant at Straumsvík just outside Hafnarfjörður. There are plans for the Suðurnes Line 2 to connect to the Hamranes substation through a 1.5km-long 220 kV underground cable extending from Hraunhella in Hafnarfjörður. The decision was also made to improve the acoustical properties of the Hamranes substation, including by encasing the transformers in sound-insulating materials and raising the noise barrier. Construction for this project commenced in late 2015 and is scheduled for completion in the first half of 2016. The works under the agreement are expected to be completed by year-end 2018, subject to all required permits being obtained in time. This project will vastly improve the visual appearance of the substation at Hamranes.
The construction of the Sandskeið Line 1 from the Sandskeið substation to Hraunhella is necessary for the demolition of the Hamranes Lines and other modifications to the grid in Hafnarfjörður under the aforesaid agreement. Landsnet’s preparations for the construction of the line and the substation at Sandskeið have already begun.
Suðurnes Line 2
Landsnet has for years been preparing the construction of the Suðurnes Line 2, which will extend from the Greater Reykjavík area onto the Reykjanes peninsula and increase security of supply in the Suðurnes region. The line route is just over 32km. In 2015, development permits were obtained from the four municipalities through which the line will be built. Preparatory works were tendered out in the autumn of 2015. Construction of the line tracks and foundations is scheduled to begin in spring 2016 and the stringing of the line is scheduled in 2017.
Krafla, Þeistareykir and Bakki
Landsnet is planning an extensive construction project in north-east Iceland for, on the one hand, the connection of the Þeistareykir Power Station to the Bakki industrial site near the town of Húsavík and, on the other hand, the connection of the power station to the grid. The project involves the construction of two 220 kV transmission lines, the Krafla Line 4, an approximately 33km line extending from the Krafla Power Station to Þeistareykir, and the Þeistareykir Line 1, an approximately 29km line extending from Þeistareykir to the Bakki site.
Three new 220 kV substations will also be built: at Krafla, a new, four-breaker substation and a connection to an older substation; at Þeistareykir, a new five-breaker substation; and at Bakki, a new three-breaker substation. We worked on the design and preparation of the project during the year. Tenders will be invited for the largest project components in the first half of 2016, with project completion scheduled in 2017.
Voltage raising in the Westman Islands
Works for the voltage raising of the Westman Islands Line 3 were prepared during the year. A new 66 kV substation needs to be constructed in the Westman Islands, and modifications are needed to the substation at Rimakot, which connects the Islands to the main grid. A contractor was appointed through a tender process, with works scheduled to start in early 2016 and to be completed by year-end. This is a partnership project between Landsnet and the multi-utilities company HS Veitur. The voltage raising of the Westman Islands cable will enable a doubling of its transmission capacity.
Reinforcement of the Mjólká substation
Landsnet has plans to bolster the West Fjords transmission network by adding one 132/66 kV transformer at the Mjólká substation. The current transformer there has reached the limit of its carrying capacity and is a bottleneck for transmission to the West Fjords. In 2015, we worked on the preparations and concluded a contract on the purchase of the new transformer. It is scheduled for delivery in October 2016 and will then be installed in the West Fjords and energised.
Cable conduits in the Norðfjörður Tunnel
After hearing about plans to construct a tunnel between the fjords Eskifjörður and Norðfjörður in East Iceland, Landsnet decided to prepare for the future by installing conduits for underground cables in the tunnel. We worked on the preparation of this project in 2015. The installation of the conduits is scheduled to begin in the first half of 2016. The tunnel itself is scheduled to be opened for traffic in late 2017.
Maintenance and repairs
Landsnet’s Grid Service division worked on around 600 O&M tasks of varying sizes and scope in 2015. Among the largest incidents Grid Service had to deal with in the year were the damage sustained by transmission towers on the Hvolsvöllur Line 1 during a lightning storm in January, wind-blown materials hitting the Suðurnes Line 1 during a storm in February, damage to towers and lines in the West Fjords and western Iceland in March and April, a fault in a transformer at the Rimakot substation, which provides the Westman Islands with electricity, in August and damage to the Rangárvellir Line 1 in the Skagafjörður region in December. Other Grid Service activities included inspection of substations and maintenance of their electrical equipment, work relating to the construction of new infrastructure, work on outage management and underground cables, and inspections and maintenance of transmission lines. This included busbar splitting at the Sigalda substation, maintenance of transformers at the Brennimelur substation, modifications to the Prestbakki Line 1 at Gígjukvísl, the renewal of the suspension equipment and insulator discs of the Geiradalur Line 1, the renewal of a conductor on the Mjólká Line 1 extending over the fjord Þorskafjörður, a conductor replacement on the Ólafsvík Line 1 in the Bláfeldarhraun lava field, modifications to connectors on the Fljótsdalur Line 4 and an interconnection for the Fljótsdalur Lines 3 and 4, to name but a few examples.