| 1. |
- Bertling, Lina, et al.
(author)
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RADPOW development and documentation
- 2008
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Reports (pop. science, debate, etc.)abstract
- This report summarizes the status of the computer program RADPOW. RADPOW is a program for Reliability Assessment of electrical Distribution POWer systems. It was developed at KTH School of Electrical Engineering, within the research program EKC and the research project on reliability of new electrical distribution systems. Further on, RADPOW has been used and further developed within the RCAM research group at KTH School of Electrical Engineering. This status report contains a brief description of the RADPOW_2006 version, the Loadflow module from the RADPOW_1999_PH version and a description of the work done in the resulting RADPOW_2007 version. This version now includes a tested load flow module and the ability to calculate the latest component importance indices developed within the RCAM research group. The source code for the program has also been restructured and commented in a more detailed level than before.
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| 2. |
- Hilber, Patrik, et al.
(author)
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Potentiell användning av standardkostnader i regleringen av elnätsföretagens löpande påverkbara kostnader
- 2010
-
Reports (other academic/artistic)abstract
- Potentiell användning av standardkostnader i regleringen av elnätsföretagens löpande påverkbara kostnader har utretts på uppdrag av Energimarknadsinspektionen (EI). Specifikt om mått baserade på Ekm kan användas i regleringen och hur dessa mått bör korrigeras. Ekm (Ekvivalent ledningslängd) är en standardkostnadsmodell där olika entiteter (t.ex. mängd av en komponentkategori) av elnät tilldelas en kvot för årlig drift- och underhållskostnad i förhållande till 1 km 0,4 kV luftledning. Projektets huvudslutsats är att existerande Ekm, tillhandahållna av Svensk Energi, inte kan användas utan rigorösa kontroller och omfattande utveckling, vilket entydigt styrks av utförda analyser. Emellertid finns det en potential att använda Ekm-liknande mått i kommande reglering. Vid ett eventuellt införande rekommenderas följande: Preliminära Ekm-liknande tal implementeras under första tillsynsperiod för en lägre andel av löpande påverkbara kostnader än ursprunglig plan (25%), förslagsvis så att de medel som omfördelas i genomsnitt blir väsentligt lägre än de medel som omfördelas på grund av kvalitetsregleringen. Noggrann utvärdering görs fortlöpande, vars resultat används för revidering av Ekm till nästkommande tillsynsperiod. Detaljerad analys och utveckling av Ekm liknande tal; förslag på handlingsplan tillhandahålls i appendix. Två enkäter har utformats, huvudenkäten har skickats ut till samtliga nätägare i Sverige. Svarsfrekvensen på denna blev 46 % (motsvarande ca 75 % av kundunderlaget). Uppföljande enkät skickades till de som angivit intresse för fördjupat deltagande (12st). Utöver enkäter bygger studien på material från EBR (del av Svensk Energi) och EI samt diskussioner med dessa och nätägare. Trots mängden empiriskt material har inga konkreta förslag på Ekm liknande mått kunnat tillhandahållas, dels på grund av stora variationer mellan svar och analyser och dels på grund av låg svarsfrekvens i enkäten för de delar som avser konkreta kostnader. I vissa fall ger enkätsvaren och analyserna indikationer på storleksordning för Ekm tal och hur dessa bör justeras. Ytterligare en osäkerhetsfaktor är huruvida nuvarande indelning är lämplig, dvs. om fler eller färre objektiva förutsättningar, t.ex. terräng, bör tas i beaktning. Detta är kopplat till den viktiga frågan om att kunna göra en analys av utfallet av ett införande, innan implementering (hur kommer intäkterna omfördelas). Detta har ej kunnat göras då företagen ännu ej rapporterat in sina nät-tillgångar. Studiens viktigaste resultat: Möjliggörande för samtliga parter att bidra med synpunkter innan eventuell skarp implementering. Inventering nuvarande förutsättningar avseende Ekm. Indikation på hur vissa mått bör modifieras. Metoder för utvärdering och bestämmande av nya mått. Ökad medvetenhet och kunskap hos myndighet och nätföretag. Handlingsplan för fortsatt arbete.
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| 3. |
- Hilber, Patrik, et al.
(author)
-
Risk analysis for power systems : overview and potential benefits
- 2010
-
Conference paper (peer-reviewed)abstract
- This paper provides a mapping and sample of recently developed risk assessment techniques that are available for the distribution system operator. Three estimates on the value of more detailed risk analysis are desccribed. I.e. component reliability importance indices can be used to divversify the maintenance efforts, gaining better expected system performance at no cost. Furthermore, components that are assumed to be relatively harmless (based on average values) are identified as critical for longer interruptions. Finally it is shown that losses in a transformer are critical in the decision on transformer lifetime.
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| 4. |
- Setréus, Johan, 1980-, et al.
(author)
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Maintenance and Investment Optimization in Distribution Systems
- 2007
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Reports (other academic/artistic)abstract
- This report desccribes a method of minimizing the reliability indices SAIDI or SAIFI for a distribution system given a limited budget and a number of possible maintenance and investment alternatives. The opposite problem, minimizing the total cost with an appropriate level of reliability, has also been modeled. The method is general and can include both investments such as a replacement of overhead line to cable or a redundant line. The result from the method is the investment alternatives that is optimal to perform at the moment. The method is desccribed in the report with the help of a test system with a number of investment alternatives and constraints. The optimization model for the test system is implemented in the computer software AMPL and evaluated with the Cplex solver. The results from the model are reasonable. In order to evaluate how stable the solution is, a sensitivity analysis has also been performed. In the closure of the report a discussion of future work and development of the method is suggested.
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| 5. |
- Setreus, Johan, 1980-, et al.
(author)
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RACalc : a Power Distribution Reliability Tool
- 2010
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In: 2010 IEEE 11th International Conference on Probabilistic Methods Applied to Power Systems (PMAPS). - : IEEE. ; , s. 154-159
-
Conference paper (peer-reviewed)abstract
- One major objective of maintenance management activities in electrical distribution systems is to find the right level of investments. Within an MSc thesis project at KTH, the probabilistic reliability software RACalc has been developed to support the decision making in the distribution system maintenance planning and risk analysis. This paper desccribes the algorithms in RACalc and shows on present status on RADPOW, an additional reliability tool developed within the research group. Calculations with RACalc is in this paper exemplified with a case study on an existing Swedish distribution system, were the program is used to determine the components’ importance to the system reliability indices. The result show that if the failure rate can be decreased by 10% on the 21% most important components, the overall system reliability improvement is more than 7%.
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| 6. |
- Wallnerström, Carl Johan, 1980-, et al.
(author)
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Model of Capacity Demand under uncertain Weather
- 2010
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In: Proceedings IEEE International Conference on Probabilistic Methods Applied to Power Systems (PMAPS). - : IEEE. - 9781424457236 ; , s. 314-318
-
Conference paper (peer-reviewed)abstract
- Load forecasting is important in the operation of power systems. The characteristics of the electrical energy consumption are analyzed and its variation as an effect of several weather parameters is studied. Based on historical weather and consumption data received from a distribution system operator (DSO), numerical models of load forecasting are suggested according to electrical power consumption and on daily peak power respectively. Two linear regression models are presented: simple linear regression (SLR) with one input variable (temperature) and multiple linear regressions (MLR) with several input variables. The models are validated with historical data from other years. For daily peak power demand a MLR model has the lowest error, but for prediction of energy demand a SLR model is more accurate.
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| 7. |
- Wallnerström, Carl Johan, 1980-, et al.
(author)
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The potential of Using EQUIVALENT COMPARISON STANDARDS to judge EFFECTIBLE COSTS in Electrical Distribution tariff regulation
- 2011
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In: CIRED2011, Frankfurt 6-9 June 2011, Paper 0646. - : CIRED. ; , s. 1-4
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Conference paper (peer-reviewed)abstract
- Sweden will implement a new tariff regulation from 2012. This paper presents results from a project initiated by the Swedish regulator, performed by the RCAM (Reliability Centered Asset Management) research group aimed to review the potential of using equivalent comparison standards to judge effectible costs. The study includes interviews and surveys distributed to every Swedish distribution system operator (DSO). However, no sharp proposal on units appropriate to use in the first regulatory period (2012-2015) could be provided, due to e.g. large variations in response from the DSOs. The study provides several results such as enabling for all parties to contribute their views before implementation; indication of how current units should be modified; increased knowledge for involved parties and an action plan for future work. The regulator’s initial idea was to apply this kind of model to 25 % of the effectible cost part during the first regulatory period, but based on this study the regulator changed this plan.
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| 8. |
- Babu, Sajeesh, 1987-, et al.
(author)
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Analyses of Smart Grid Technologies and Solutions from a System Perspective
- 2015
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In: Smart Grid Technologies - Asia (ISGT ASIA), 2015 IEEE Innovative. - : IEEE conference proceedings. - 9781509012374 ; , s. 1-5
-
Conference paper (peer-reviewed)abstract
- 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.
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| 9. |
- Bergerland, Sune, et al.
(author)
-
Summary of the Swedish tariff regulation and impact of changes on investment strategies
- 2015
-
Conference paper (peer-reviewed)abstract
- 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.
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| 10. |
- Bertling, Lina, et al.
(author)
-
Evaluation of the Customer Value of Component Redundancy in Electrical Distribution Systems
- 2005
-
In: Power Tech, 2005 IEEE Russia. - : IEEE. - 9785932080344 ; , s. 1-8
-
Conference paper (peer-reviewed)abstract
- A new regulatory model for the Swedish electrical distribution system operators has been proposed, and is now being implemented. The model is referred to as the Network Performance Assessment Model (NPAM). The NPAM is based on fictive reference networks. These emanate from a radial network that is reinforced with redundant components if it increases the customer value more than required investment cost for higher system reliability. The NPAM involves a paradigm shift for the Swedish DSO from a system based on compensation for costs to one based on performance. Evidently, it is of great importance to both the regulator and the different DSOs to evaluate how well the NPAM calculates the performance i.e. the customer values. The aim for this paper is to take a first step in this process; by putting light on how these redundant reference networks are created and used for the NPAM. In order to do this a comparative study has been made for a small test system where two different approaches are used for identifying the resulting redundant reference network for a system. The NPAM approach uses a Monte Carlo simulation technique, and the comparative approach uses an analytical based reliability assessment tool RADPOW, developed at KTH.
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