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- Alvarez Perez, Manuel Alejandro, 1980-
(författare)
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Stochastic Planning of Smart Electricity Distribution Networks
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The penetration of intermittent Distributed Generation (DG) brought additional uncertainty to the system operation and planning. To cope with uncertainties the Distribution System Operator (DSO) could implement several strategies. These strategies range from the inclusion of smart technologies which will increment system’s flexibility and resiliency, to improvements in forecasting, modeling, and regulatory pledge that will facilitate the planning activity. Regardless of the nature of the solutions, they could be collected in a sort of toolbox. The planner will access the toolbox to conform cost effective plans, better able to deal with any uncertainty. The present work will address the problem of distribution system planning under uncertainties, considering smart solutions along with traditional reinforcements, in the short-term lead time up to 3 years ahead. The work will be focused on three aspects that are the cornerstones of this work: • A planning facilitating strategy: Distribution Capacity Contracts (DCCs). • A flexibility enabler technology: Energy Storage. • A binding methodology: Multistage Stochastic Programming. Stochastic dual dynamic programming (SDDP). Under the present directive of the European Parliament concerning common rules for the internal market in electricity, distribution companies are not allowed to own DG but entitled to include it as a planning option to differ investment in traditional grid reinforcements. An evaluation of the regulatory context will lead this work to consider DCCs as a planning alternative available in the toolbox. The impact of this type of contract on the remuneration of the DG owner will be assessed in order to provide insight on its willingness to participate. The DCCs might aid the DSO to defer grid i ii investments during planning stages and to control the network flows during operation. Given that storage solutions help to match in time production from intermittent sources with load consumption, they will play a major role in dealing with uncertainties. A generic storage model (GSM) based on a future cost piecewise approximation will be developed. This model inspired by hydro-reservoirs will help assessing the impact of storage in planning decisions. This model will be tested by implementing it in short-term hydro scheduling and unit commitment studies. To trace a path towards the future of this research work, a discussion on the planning problem formulation, under consideration of the lead time, the expansion options, the smart strategies, and the regulatory framework will be presented. Special focus will be given to multistage stochastic programming methods and in particular to the SDDP approach.
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| 2. |
- Nömm, Jakob, et al.
(författare)
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Energy Flow Based Risk Analysis for Operating A Standalone Solar-Hydrogen Nanogrid in Northern Scandinavia
- 2019
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Ingår i: 2019 Nordic Workshop on Power and Industrial Electronics (NORPIE). - : IEEE. - 9798350331998 ; , s. 65-73
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Konferensbidrag (refereegranskat)abstract
- In this paper, an energy flow model for a standalone nanogrid was used to calculate the needed hydrogen storage for operation in northern Scandinavia where the electricity was produced from solar photovoltaics. A range of different input parameters such as annual energy consumption, solar production, consumption pattern and heating system was used to obtain a range of optimal system design parameters. From this, two average system configurations were created for two heating systems based on the results from simulated solar data with 2-axis solar tracking and no solar tracking. The average value from the results at 30 MWh of annual energy consumption was used since it is the average energy consumption for a household in northern Sweden. The average system configuration was applied for 15 to 40 MWh of annual energy consumption using 3 measured solar production datasets and 37 different consumption patterns to study the risk for depleting the hydrogen storage and counter measures to avoid depletion. The results show that energy saving measures must be taken during the winter in order to avoid depletion of the hydrogen energy storage, which in turn avoids a sustained interruption until the spring. It was concluded that if 2-axis solar tracking was used instead of no tracking and a stove was used for heating instead of using a heat pump, the probability for depleting the hydrogen storage reduced by 25% to 47.9% at 30 to 40 MWh of annual energy consumption in the nanogrid.
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| 3. |
- Schwanz, Daphne, et al.
(författare)
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Stochastic Assessment of Voltage Unbalance due to Single-Phase-Connected Solar Power
- 2016
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Ingår i: 2016 17th International Conference on Harmonics and Quality of Power. - Piscataway, NJ. - 9781509037926 ; , s. 95-103
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Konferensbidrag (refereegranskat)abstract
- A stochastic method is presented in this paper to estimate the future voltage unbalance in a low-voltage distribution network with high-penetration of single-phase photovoltaic inverters (PVIs). Location and phase allocation of the PVIs are considered as input parameters for the stochastic simulation. The method has been applied to three different low-voltage networks: two in Sweden and one in Germany. In the Swedish networks, for 6-kW single-phase PVIs, it is likely that the contribution from single-phase photovoltaic inverters to the voltage unbalance exceeds 1%. The 2% value is unlikely to be exceeded. In the German network, for 4.6-kW single-phase PVIs the voltage unbalance is between 1.35% and 2.62%. The risk of high voltage unbalance can be reduced by a combination of controlled distribution over the phases and reduction of the maximum size for a single-phase PVI.
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