The electric power system is being modernized to enable sustainable energy. This chapter presents analyses of different new technologies and solutions for such modernized power systems. Analyses presented include the integration of wind and solar power, electricity consumption, dynamic rating, and energy storage. The main contribution is to considerate effects of weather parameters to find synergies. A national smart grid demonstration project at Gotland island in Sweden has been used as the case study. Results show how the power systems can handle more electricity consumption and generation. The study shows new technology solutions that are beneficial for resource-efficient electricity grids. The case study results show that, most of the time, the energy storage will be unused, but that it can be used to increase the system reliability during that time.

Dynamic line rating is a novel technique used to determine the actual value of available power transmission capacity of overhead lines being underestimated by static line rating. Contrary to static line rating method, this approach provides huge technical and economic benefits of transmitting the electrical energy under controlled constraints. Nevertheless, it is of utmost importance to have an accurate knowledge of dynamic ampacity before being practically implemented. Owing to dynamic line rating technique, an overhead conductor is rated on the basis of real-time ampacity. Furthermore, the real time ampacity contributes in combating the growing power transmission demand being observed over highly congested power transmission network. Contrary to dynamic line rating approach, building new overhead lines is a lengthy, expensive, and less reliable option. Another important advantage offered by the dynamic line rating approach is to allow excessive renewable power generation in the electricity network, particularly the wind power due to its correlation with real-time ampacity. Besides, dynamic ampacity and wind power integration, the paper also deals with risk analysis associated with conductor overloading. The risk involves increase in conductor sag as it transmits the power beyond its nominal capacity at a certain temperature. However, in this paper, the dynamic as well as the static ampacity of “VL3” overhead conductor is calculated on the basis of its nominal temperature (50 °C) to avoid the risk of its possible expansion and ultimately the deterioration. In addition to technical analysis, the economic analysis of integrating a 60 MW wind park with Fortum's 130 kV regional grid and of applying dynamic line rating approach on a periodically overloaded “VL3” overhead conductor is thoroughly investigated in this research work; to further know how beneficial it is to temporarily postpone the rebuilding and/or construction of a new overhead line in parallel to the existing overhead conductor (VL3).

This paper presents results from a study on the impact of smart grid solutions, which includes development of a generic framework for power system analyses. The study has been performed as one of several independent studies, part of a national governmental task on smart grid in Sweden. A large amount of weather data, along with electricity consumption and wind power generation data, have been analyzed. Achieved results from these initial analyses can be used as reference material and have also been used within case studies presented. The proposed framework is flexible and numerous combinations of scenarios are possible to define. Integration of wind and solar power, analyses of transfer limits using static or dynamic rating and energy storage can be considered as well as weather effects. Results show how power systems can handle more electricity consumption and generation. The study shows that Smart Grid solutions are beneficial for resource efficient electricity grids. Moreover, different risk levels with respect to increased load can be included. Case study results show that energy storages most of the time will be unused, but that they can be used to increase the system reliability.

This paper consolidates the data, analysis andobservations from a case study conducted in cooperation withthe Smart Grid Gotland project. The analysis identifies howelectrical power consumption interacts with distributedelectricity generation such as wind and solar power andpresents how it correlates to weather data and smart gridsolutions. The analysis model developed based on the Gotlandnetwork is generic and hence can be functional in investigatingother power networks of different size, voltage level andstructures. The key observations from the study of smart gridsolutions such as dynamic load capacity and energy storagesolutions are specified. Based on the project, an overview offuture risks and opportunities of smart grid systems is presented.

The concept of dynamic rating (DR) implies that the capacity of a component varies dynamically as a function of external parameters, while the rating traditionally is based on the worst-case. The value of DR thus lies in utilizing existing equipment to a greater extent. By implementing DR and correlating the new ratings with wind power generation, more generation can be implemented. The aim is hence to facilitate connection of renewable electricity production. This paper provides two main contributions: 1) a general dynamic line rating (DLR) calculation model on overhead lines; and 2) an economic optimization simulation model regarding wind power integration comparing DLR with more traditional approaches. These models can both be implemented together, but also separately. The DLR calculation model is easy to use by companies in daily operation where the dynamic line capacity is calculated as a function of static line capacity, wind speed, and ambient temperature. The DLR calculation model is furthermore compared with more comprehensive calculations that validate that the model is accurate enough. This paper also provides an application study where both proposed models are exemplified together and evaluated. Results from this study conclude that it is a significant economic potential of implementing DR within wind power integration.

 Based on conventional static line rating method, the actual current carrying capability of overhead conductors cannot be judged. Due to continuous increment in electricity demand and the difficulties associated with new line constructions, the overhead lines are therefore required to be rated based on a method that should establish their real-time capability in terms of electricity transmission.

The method used to determine the real-time ampacity of overhead conductors not only can enhance their transmission capacity but can also help in allowing excessive renewable generation in the electricity network. In this research work, the issues related to analyzing an impact of wind power on periodical loading of overhead line as well as finding its static and dynamic ampacities with line current are investigated in detail. Moreover, the investigation related to finding a suitable location for the construction of a 60 MW wind farm is taken on board. Thereafter, the wind park is integrated with a regional grid, owned by Fortum Distribution AB. In addition to that, the electricity generated from the wind park is also calculated in this project. Later on, the work is devoted to finding the static and dynamic line ratings for “VL3” overhead conductor by using IEEE-738-2006 standard. Furthermore, the project also deals with finding the line current and making its comparison with maximum capacity of overhead conductor (VL3) for loading it in such a way that no any violation of safe ground clearance requirements is observed at all. Besides, the line current, knowing the conductor temperature when it transmits the required electricity in the presence of wind power generation is also an important factor to be taken into consideration.

Therefore, based on real-time ambient conditions with actual line loading and with the help of IEEE-738-2006 standard, the conductor temperature is also calculated in this project. At the end, an economic analysis is performed to evaluate the financial advantages related to applying the dynamic line ratings approach in place of traditional static line ratings technique across an overhead conductor (VL3) and to know how much beneficial it is to temporarily postpone the rebuilding and/or construction of a new transmission line. Furthermore, an economic analysis related to wind power system is taken into consideration as well to get familiar with the costs related to building and connecting a 60 MW wind farm with the regional grid.

This paper evaluates how upcoming changes in the Swedish tariff regulation could affect distribution system operators (DSOs), with focus on reinvestment planning. This is done by general analyses as well as by authentic calculation examples of a real power distribution system. The paper describes the Swedish tariff regulation with expected changes, provides a summary of changes in Swedish laws and regulation affecting DSOs between 1996 and 2016, describes how a DSO at local distribution level conduct their reinvestments, illustrates economic calculation examples and finally presents analyses and conclude the results. Analysis results presented show that the outcome from the regulation is sensitive towards relatively small changes in WACC and age structure. The tariff cap allowed will however be significantly reduced for all tested scenarios. A reinvestment rate of in average~10 % regarding meters and IT and ~2.5 % regarding all other categories could be a rough guideline to meet the new incentives, but that could differ depending on the actual age structure of the DSO.

Denna rapport presenterar resultat från en studie där inverkan av så kallade smartaelnäts­teknologier/lösningar har analyserats. Utöver egna analysresultat identifieras behov av framtida forskning, detta kompletteras med hänvisningar till fördjupningsmaterial Smarta­elnätsteknologier innebär nya möjligheter, men också nya utmaningar och risker. Ett behov av att utveckla nya metoder för tillförlitlighetsberäkningar och riskanalys har identifieras. På grund av bristande erfarenhet gällande många nya tekniker och lösningar av smartaelnäts­teknologier är det värdefullt med demonstrationsanläggningar såsom Smart Grid Gotland, varifrån indata har erhållits. Information om Smart Grid Gotland och Gotlands elkraftsystem sammanfattas i rapporten. Gotlands regionnät har även implementerats i datorverktyget NEPLAN. En visuell modell av ett elnät med integrerade smartaelnätsteknologier som kan illustrera möjligheter och utmaningar ur ett systemperspektiv. I rapporten behandlas även frågan om framtida kompetensbehov till följd av smarta elnät ur ett riskperspektiv.

En stor mängd timvis väderdata har bearbetats och analyserats tillsammans med timvis data för elkonsumtion och lokal elproduktion. Samband mellan olika parametrar har identifierats, vilka kan vara värdefulla att använda sig av vid utvecklandet av smarta lösningar i elnätet. Resultat från denna initiala analys av indata har använts i genomförda analyser, men kan även vara användbarts referensmaterial i andra studier. Ett analysverktyg har tagits fram för att analysera integrering av elproduktion från både vindkraftturbiner och solkraft, analys av acceptgränser, dynamisk belastningsförmåga och energilager. Hänsyn tas till vädrets påverkan på elproduktions- och elkonsumtionsmönster samt överföringskapacitet.

Dynamisk belastningsförmåga innebär att systemets överföringskapacitet varierar dynamiskt med avseende på externa parametrar såsom väder, vilket ökar möjligheten att nyttja ekraft­system mer effektivt. Analysresultat från flera olika scenarion presenteras i rapporten, vilka visar på olika exempel avseende hur elnätet kan hantera högre maxnivå av elkonsumtion och/eller elproduktion utan fysiska nätförstärkningar. I rapporten presenteras även exempel på hur denna lösning i vissa fall kan öka leveranssäkerhet. Potential av att använda sammanlagring mellan elkonsumtion och lokal elproduktion har analyserats, det vill säga hur dessa tar ut varandra. Även resultat för olika risknivåer med avseende på överlast har analyserats för flera olika scenarier, med och utan dynamisk belastningsförmåga. Om över­last endast medför ökat slitage går det att tänka sig att det kan tillåtas under korta perioder.

Energilagring har analyserats ur ett teknikneutralt perspektiv och resultat redovisas som kravlistor. Av elproduktion från vindkraftturbiner respektive solkraft och elkonsumtion kan ett lika stort energilager höja maxeffekten av solkraft mer jämfört med övriga analyserade kategorier. Även energilager i systemdel innehållendes både elkonsumtion och elproduktion, vilken har problem med både import- och exportbegränsningar, har analyserats. Denna kombination balanserar ofta varandra så att överlast undviks; energilagret tar hand om de två ytterligheterna: export- respektive importtoppar. Hur energilager potentiellt kan användas för att höja leveranskvalitet har också analyserats. Energilager som hanterar överföringstoppar behöver endast användas under en liten period av årets timmar och skulle därför kunna användas för flera olika saker såsom att öka leverenssäkerhet.

I ett appendix till rapporten görs en ansats till att koppla studiens innehåll till rekommendationer presenterade i Samordningsrådet för smarta elnäts handlingsplan.

There is an international tendency toward increased demand for both cost-efficiency and high reliability of power distribution systems. To meet these demands, asset management methods, including reliability analyses, have been developed. These reliability analyses often utilize only mean values and hence do not take into consideration the consequences of severe events. This paper proposes a framework for more detailed quantitative risk analysis methods. The aim is to allocate resources more cost-effectively. The suggested framework is exemplified and evaluated by implementing it within the analyses of a real power distribution system. The main concept is to divide comprehensive projects into minor analyses and then in a final step compile the results. The proposed analysis framework can be used independently or combined with earlier proposed vulnerability methods. The latter provides a two-dimensional analysis framework. It is shown that totally different investment alternatives could be preferred depending on whether a traditional analysis method using average values is employed compared with the proposed analysis framework, which also considers severe system states. This demonstrates the risks involved in using average values and the strength of the proposed method. Furthermore, it is shown that already available information can be used for improved asset management decision support. In addition, the performed case study gives combined reliability and weather statistics useful as reference material.