Nordic countries establish common cooperative standards for major system outages.
There are disasters an organization manages and then there are disasters that manage the organization. Major failures on the power system can lead to physical and financial losses, liability claims and severe business continuity impacts, including loss of reputation. However, if managed effectively, power systems can enhance reputations and provide opportunities for future growth and development.
The Nordic power transmission system has had long-term reliability of the highest standard with very few major or large-scale system disturbances. To maintain these standards and be capable of handling extremely large-scale physical breakdowns of the transmission system, the transmission system operators (TSOs) in the Nordic countries — namely, Denmark, Finland, Iceland, Norway and Sweden — have worked together to establish a common Nordic fault-repair strategy.
Every Nordic country has an independent TSO that owns and operates the country's main transmission system. Each TSO has selected a different approach to the fault-repair format, depending on the volume of work undertaken by TSO staff compared with that which is outsourced and completed by contractors. None of the Nordic TSOs have sufficient resources to perform all work in-house, and all of the TSOs award contracts to contractors for the construction of new transmission lines.
Since the early 2000s, the energy authorities of the Nordic countries have held regular meetings to discuss contingency planning and the management of the Nordic power sector. The Nordic Forum for Emergency Matters (NordBer), consisting of all the energy authorities, TSOs and other organizations in the power industry, has been working together for more than a decade, exchanging information and experience. A major goal of NordBer is to establish a higher level of readiness to manage major system outages at a lower cost by planning and developing cooperation between countries and across utility borders.
NordBer established a working group called Recovery Assistance for Main Grid Major Breakdowns to examine different sectors of cooperation in the field of contingency planning. The administration of this working group is now managed by the Nordic Asset Management Forum (NordAM) for TSOs. This forum was created to enhance cooperation between the Nordic TSOs' asset management organizations and to ensure knowledge sharing among the asset management specialists.
The Recovery Assistance for Main Grid Major Breakdowns working group has members from each TSO as well as representatives from the contracting companies who undertake transmission line construction. Although the contingency planning cooperation is focused on transmission system voltages above 200 kV, similar cooperative strategies for distribution system voltage network levels have been considered. Since 2000, this working group has been focused on developing a common Nordic recovery-assistance process.
A well-managed emergency repair strategy demands sufficient critical reserve components and resources with appropriate skills and tools who have been trained on repair work procedures. Therefore, the first step toward implementing the strategy was to survey the existing resources, materials, equipment and contingency policies used by each Nordic TSO.
The survey identified differences and targets for major breakdown scenarios. It also noted — at least for one Nordic country following a major power line breakdown in which dozens of towers collapsed — that the TSO's resources in terms of equipment for emergency use and personnel were insufficient for restoring the grid within a reasonable time period. As a result of these findings, the working group developed procedures for ensuring safe and successful assistance missions between countries for the restoration of major transmission overhead line breakdowns.
The Main Risk
The failure of transmission line towers as a result of weather phenomena constitutes the primary threat to transmission systems on the Nordic grid. Such phenomena could include a hurricane or super-cold rain that creates ice accretion on the overhead line conductors and tower structures, making it possible for the increased weight to cause towers to collapse.
The Nordic countries have been fortunate not to experience a wide-scale major outage to the transmission system since the formation of the working group. However, there was a large-scale breakdown at regional and distribution grid voltage levels on Jan. 8, 2005, when the winter storm Gudrun hit Denmark and southern Sweden. This storm took out power to 341,000 homes in Sweden. Thousands were without power for many days, and no fewer than 10,000 homes were without power for more than three weeks. The resources employed for this system restoration included 600 linemen from 100 Swedish companies and more than 400 linemen from 35 foreign companies. Restoration took more than three weeks, and the maximum number of people working simultaneously exceeded 2,700.
The Nordic Recovery Handbook
The procedures established by the working group now form a set of structurally indexed files consisting of spreadsheets, text documents, drawings and photos. They contain details on resource requirements, information on the differences in materials, tools and equipment used in each member country, and information on how the different materials and equipment can be used together, if necessary. This data bank (The Nordic Recovery Handbook) is supervised by a steering group comprising members of staff from each TSO who review and update this information annually. The Nordic Recovery Handbook contains seven sections with information on different topics that are useful or must be considered when seeking or providing recovery assistance.
Several lessons have been learned from this cooperation:
The importance of having competence and safety issues resolved in advance
Methods for organizing a foreign workforce
Employer's responsibilities when linemen are temporarily working for a third party.
To formally agree to the cooperation plans between TSOs, a letter of intent regarding recovery assistance among the countries and companies was established. All the Nordic TSOs signed the letter in the spring of 2009. As the cooperation is entirely based on the common goodwill of assisting a neighboring TSO, all parties considered it acceptable to keep this agreement on a letter-of-intent basis rather than a legally conclusive agreement.
As the established contingency plans have not been used for a major incident, the recovery procedures have been evaluated against possible major breakdown scenarios through workshops and tabletop exercises. Participants in this training have included personnel from TSOs, regional and distribution grid (voltages less than 200 kV) utilities, and transmission line contractors. The results of these training exercises revealed that several procedures require improvement. They were rolled back into the contingency development process, and the recovery-assistance handbook was updated with the improvements.
The workshops and training exercises have improved the knowledge sharing on contingency planning, work methods and routines. The feedback from participants has been highly positive, especially with regard to the value of social networking. Meeting and getting to know colleagues in other Nordic countries who are engaged in working to rebuild after major breakdowns has been quite important.
A procedure for an assistance request has been developed that includes a contact list. This contact is only the first step for an assistance mission, and the agreed-to procedure recommends that every company should have a planned internal process in place regarding assignments to other Nordic countries. This should including identifying the resources, materials and equipment available for use and how these resources should be prepared, equipped and transported to the country seeking assistance.
The material, tools and machinery section of the plan consists of three key subjects: emergency towers, materials and tools, and machinery covering all the TSOs and main contractors. In each Nordic country, the rapid response emergency towers consist mainly of guyed single-circuit 110-kV to 400-kV towers made of aluminum or steel. The aim of this tower design is versatile use, fast transport and easy assembly.
The materials most important for emergency purposes — namely, insulators, conductors, and conductor joints, fittings and clamps — are among the materials stored in shipping containers that can be easily and rapidly shipped to another country. These containers usually have all the equipment (insulators, fittings and clamps) needed for a single tower. The tools and machinery section consists of the most critical items that may be needed for an assistance mission, so hand tools and personal equipment are not included. However, cross-country vehicles, winches, crawler tracks, cranes, bulldozers, tensioners and pulling machines are included. Details of each company's store of towers, tools and machinery are available to each member country.
Additional Supporting Procedures
Customs regulations need to be considered when seeking assistance from other countries. As the Nordic countries of Denmark, Finland and Sweden belong to the European Union, there are no customs regulations that would prevent import or export of equipment for a system emergency mission.
Although Iceland and Norway are not part of the European Union, their customs procedures in an emergency situation are similar. The import and export of goods can take place without a customs declaration. Only a list of the material, equipment, tools and vehicles has to be presented at the border. On completion of the mission, customs authorities will then check that the same materials are returned to the original country. Materials used during the recovery are declared on completion of the mission.
Resources and Their Competencies
To identify the availability of workers, the working group has collected data from member countries on the resources that could be made available, as well as detailed records of team leader and team member competencies:
Linemen familiar with working on long spans (fjord crossings)
Linemen trained for work on steel towers
Linemen trained for work on wood poles
Linemen trained for work on overhead line conductors
Linemen trained for working with special equipment (conductor tensioning)
Linemen trained for working with fiber-optic ground wires.
The most important qualifications when working on power lines, in addition to professional skills, are a knowledge of electrical safety regulations, competence to work on transmission line and competence to work near public roads. Fortunately, the regulations in Nordic countries, which in many respects are common throughout Europe, are very similar with few differences. Nearly every country follows the safety principles specified in European Standard 50110-1, operation of electrical installations with regard to electrical safety. Although there is no need for further training of the mobilized staff, a short presentation is needed to clarify the possible differences in regulations, terms and working arrangements.
It is natural for language problems to arise when people from different nationalities work together. Such problems can be largely avoided in several ways:
Place linemen under the command of a local team leader
Place a lineman or a team leader on a crew who has at least some additional language skills
Form mixed teams using local and foreign linemen
Delegate work and responsibilities in a proper manner
Designate clearly defined working areas for foreign teams
Use common vocabularies.
The use of two vocabularies is presented in two handbooks. The first is the more extensive version, containing the most common words used when working on transmission lines; the second is a pocket-sized phrase book meant for a lineman's everyday use.
The recovery handbook does not contain all the international and national requirements and standards that could be useful during an assistance mission. However, several agencies and companies provide the needed information through different online sites, the links of which are documented in the handbook files.
Ready to Deploy
Nordic TSOs, regional network owners and transmission line contractors have considered contingency planning and cooperation across borders as very useful. The development process of establishing the recovery-assistance strategy, done in close cooperation, has been valuable for all parties. It is important all participants remain committed to the mission and they participate in the process with an open mind (ready to share information even if the information could be classified as somewhat confidential or strategically important).
The formation of the files and training undertaken has not primarily lowered costs for contingency plans, but this cooperation of recovery assistance is widely developed, practiced and available to be put into operation whenever any TSO in the Nordic countries lacks sufficient resources to effectively manage and restore power supplies in the event of a major transmission system outage.
The author wishes to acknowledge the support given by the Long-Term Recovery Assistance for Main Grid Major Breakdowns working group partners, Leif Vikane from Statnett AS in Norway and Göran Bredvad-Jensen from Svenska Kraftnät
Marcus Stenstrand (firstname.lastname@example.org) is the maintenance manager for transmission lines in Fingrid Oyj. Since joining Fingrid Oyj in 1997, Stenstrand has been developing and training for emergency repair work in Finland and internationally as a result of his membership on the Nordic Recovery Assistance for Main Grid Major Breakdowns working group from 2000 to 2009. Stensstrand holds a BSEE degree from Arcada University of Applied Science and a MBA degree from Hanken School of Economics, both in Helsinki.
Transmission System Statistics for Nordic Countries
Together, the Nordic countries have a total area of 1,257,000 sq km (485,330 sq miles), an installed generating capacity of 92.6 GW and a population of 24.5 million who consume some 400 TWh per annum. The national transmission systems of the five Nordic countries, with the exception of Iceland, are interconnected.
|Country||Transmission system operator||Length of transmission system|
|Denmark||Energinet.dk||1,600 km (994 miles)|
|Finland||Fingrid Oyj||14,300 km (8,886 miles)|
|Iceland||Landsnet||3,200 km (1,988 miles)|
|Norway||Statnett SF||9,600 km (5,965 miles)|
|Sweden||Svenska Kraftnät||15,000 km (9,321 miles)|
Svenska Kraftnät www.svk.se
Nordic co-operation www.norden.org/en