| 1. |
- Angioni, A., et al.
(författare)
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A distributed automation architecture for distribution networks, from design to implementation
- 2018
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 15, s. 3-13
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Tidskriftsartikel (refereegranskat)abstract
- With the current increase of distributed generation in distribution networks, line congestions and PQ issues are expected to increase. The smart grid may effectively coordinate DER, only when supported by a comprehensive architecture for automation. In IDE4L project such architecture is designed based on monitoring, control and business use cases. The IDE4L instance of SGAM architecture is derived and explained in details. The automation actor are specified in terms of interfaces, database and functions. The division in these three layers boosted the implementation phase as dedicated interfaces, databases or application has been developed in a modular way and can be installed in different HW/SW. Some implementation instances are presented and the main output of the architecture is discussed with regards to some indexes as communication traffic and level of distribution of automation functions.
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| 2. |
- Babazadeh, Davood, et al.
(författare)
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Distributed Security-Constrained Secondary Control of HVDC grids in the Presence of Wind Uncertainty
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Ingår i: Sustainable Energy, Grids and Networks. - 2352-4677.
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a distributed coordination of converters in an HVDC grid in order to provide close-to-real-time optimal DCvoltage and power profiles in the presence of wind uncertainty. This coordination is a part of HVDC grid secondary control actionthat carries out after the automatic primary control response by DC voltage droop controlling converters. It aims to optimize thegrid operation by finding the new DC power and voltage set-points that minimize the operational costs due to wind fluctuations andprediction error. Furthermore, the N-1 secure operation of HVDC grid is considered in this distributed coordination by adding a setof security constraints that tightens the upper and lower bounds of the problem variables. The coordination problem is formulatedas a convex optimization problem and therefore a modified version of alternating direction method of multipliers is adopted to solvethe problem in distributed manner. The performance of distributed coordination has been tested by a set of scenarios. The resultsimply that the distributed coordination is eligible in terms of time and complexity to be considered as either the main option forsecondary coordination or a complementary back-up solution for the central coordination.
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| 3. |
- Basati, Amir, et al.
(författare)
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Robust internal model-based voltage control for DC microgrids : An LMI based H∞ control
- 2023
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier BV. - 2352-4677. ; 35
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Tidskriftsartikel (refereegranskat)abstract
- This paper aims to design a robust internal model-based voltage control (RIMVC) scheme for DC Microgrids (DCMGs) in the presence of unknown external disturbances. Maintaining voltage reference tracking under measurement noise, delays, model parameter uncertainties and unknown external disturbances while the load changes simultaneously is a severe challenge for the DC–DC converters in DCMGs. By developing a modified internal model-based voltage control for DC–DC converters, this work proposes a plug-and-play (PnP) robust voltage control scheme to address the abovementioned challenge. The proposed control method has a cascade structure. In the first step, a modified IMC control is designed to achieve desired tracking performance for a nominal dynamical system. In the next step, the output feedback H∞ control part is added to improve the performance robustness under external disturbances and parameter uncertainties. The efficiency of the proposed control scheme is evaluated using a real-time MATLAB/Simulink testbed, taking into account unknown internal and external disturbances under various rapid voltage reference changes, model parameter uncertainties, constant power loads, system delays and normal load profile changes in multiple case study scenarios.
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| 4. |
- Blomgren, E. M.V., et al.
(författare)
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Grey-box modeling for hot-spot temperature prediction of oil-immersed transformers in power distribution networks
- 2023
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Ingår i: Sustainable Energy, Grids and Networks. - 2352-4677. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- Power transformers are one of the most costly assets in power grids. Due to increasing electricity demand and levels of distributed generation, they are more and more often loaded above their rated limits. Transformer ratings are traditionally set as static limits, set in a controlled environment with conservative margins. Through dynamic transformer rating, the rating is instead adapted to the actual working conditions of the transformers. This can help distribution system operators (DSOs) to unlock unused capacity and postpone costly grid investments. To this end, real-time information of the transformer operating conditions, and in particular of its hot-spot and oil temperature, is required. This work proposes a grey-box model that can be used for online estimation and forecasting of the transformer temperature. It relies on a limited set of non-intrusive measurements and was developed using experimental data from a DSO in Jutland, Denmark. The thermal model has proven to be able to predict the temperature of the transformers with a high accuracy and low computational time, which is particularly relevant for online applications. With a six-hour prediction horizon the mean average error was 0.4–0.6 °C. By choosing a stochastic data-driven modeling approach we can also provide prediction intervals and account for the uncertainty.
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| 5. |
- Borsche, Theodor S., et al.
(författare)
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Stochastic control of cooling appliances under disturbances for primary frequency reserves
- 2016
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier BV. - 2352-4677. ; 7, s. 70-79
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Tidskriftsartikel (refereegranskat)abstract
- To stabilize power system frequency both in normal operation and after a contingency, a hierarchy of distributed-proportional and centralized-integral controllers is employed in most power systems. Providing proportional control–commonly referred to as primary frequency control or droop–with conventional generators constitutes significant cost. This led to strong interest in utilizing demand response as a cost-effective primary control reserve. This paper investigates an approach that allows a population of domestic refrigerators to reliably and continuously adjust its demand proportional to system frequency. The control relies exclusively on stochastic switching of refrigerators, and thus avoids synchronization and implementation issues associated with control strategies based on temperature-band adjustments. The scheme is tested on a realistic two-area power system model to investigate interaction with system frequency. The modeling of refrigerators is refined by analyzing the effect of door openings on cooling demand, and response of the refrigerator population under these conditions is described both analytically and with simulations.
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| 6. |
- Chompoobutrgool, Yuwa, et al.
(författare)
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Using PMU signals from dominant paths in power system wide-area damping control
- 2015
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 4, s. 16-28
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Tidskriftsartikel (refereegranskat)abstract
- This article presents a comprehensive study of dominant inter-area oscillation path signals and their application for power system wide-area damping control (WADC). The analysis, carried out on both small and large study systems, focuses on the relationships that emerge from physical characteristics of inter-area oscillations, namely the modal observability of signals from dominant paths and their corresponding control loop system properties (i.e. stability and robustness). The aim is to be able to appropriately exploit the dominant path signals for the mitigation of inter-area oscillations. Guidelines and considerations are provided to facilitate the design of WADC using the proposed approach.
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| 7. |
- de Haan, J. E. S., et al.
(författare)
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Stabilising system frequency using HVDC between the Continental European, Nordic, and Great Britain systems
- 2016
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 5, s. 125-134
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Tidskriftsartikel (refereegranskat)abstract
- For future efficiency improvement of the frequency containment process (primary control) within European power systems, cooperation between (multiple) synchronous areas using their controllable HVDC interconnections is optioned. However, the differences in system size, HVDC interconnection capacity, and the balancing performance per individual system will have its specific system frequency effect for each different balancing cooperation concept. Consequently, without alignment on cooperation, HVDC balancing might lead to disproportional support between systems, to frequency oscillations, reserve unreliability and non-compliancy, and to network constraints. Therefore, this work assesses frequency quality and associated DC power flows for several balancing arrangements, using a developed load-frequency control model with frequency interdependency for coupled power system. For a trilateral balancing cooperation case study, it is found that certain cooperation concepts result in undesired frequency oscillation and poor frequency quality. However, cooperation where especially fast-response services are shared, such as virtual inertia, show improved system frequency performance. For the case where power imbalances are proportionately distributed among the systems, it is concluded that power transfers over HVDC interconnections are limited and additional control optimisation can be performed. Those concepts with aligned central or coordinated control show best results for a future cooperation for balancing between synchronous areas.
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| 8. |
- Fachrizal, Reza, 1993-, et al.
(författare)
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Combined PV-EV hosting capacity assessment for a residential LV distribution grid with smart EV charging and PV curtailment
- 2021
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier BV. - 2352-4677. ; 26
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Tidskriftsartikel (refereegranskat)abstract
- Photovoltaic (PV) systems and electric vehicles (EVs) integrated in local distribution systems are considered to be two of the keys to a sustainable future built environment. However, large-scale integration of PV generation and EV charging loads poses technical challenges for the distribution grid. Each grid has a specific hosting capacity limiting the allowable PV and EV share. This paper presents a combined PV-EV grid integration and hosting capacity assessment for a residential LV distribution grid with four different energy management system (EMS) scenarios: (1) without EMS, (2) with EV smart charging only, (3) with PV curtailment only, and (4) with both EV smart charging and PV curtailment. The combined PV-EV hosting capacity is presented using a novel graphical approach so that both PV and EV hosting capacity can be analyzed within the same framework. Results show that the EV smart charging can improve the hosting capacity for EVs significantly and for PV slightly. While the PV curtailment can improve the hosting capacity for PV significantly, it cannot improve the hosting capacity for EVs at all. From the graphical analysis, it can be concluded that there is a slight positive correlation between PV and EV hosting capacity in the case of residential areas.
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| 9. |
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| 10. |
- Hooshyar, Hossein, et al.
(författare)
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Specification, implementation, and hardware-in-the-loop real-time simulation of an active distribution grid
- 2015
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the IDE4L project reference grid model developed to serve as a benchmark for studies on distribution grid dynamics within the project. The paper demonstrates a MATLAB/Simulink implementation of the reference grid to be used in real-time hardware-in-the-loop simulations. The simulations will be carried out to study distribution grid dynamics and to evaluate the techniques developed in IDE4L project for TSO/DSO interactions. Performance of the grid model is shown through sample real-time simulation results and a hardware-in-the-loop setup for PMU-based grid monitoring applications.
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| 11. |
- Jian, J., et al.
(författare)
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Multi-stage supply restoration of active distribution networks with SOP integration
- 2022
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier Ltd. - 2352-4677. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- Supply restoration from outages is essential for improving the reliability of active distribution networks (ADNs) after fault isolation. Soft open point (SOP) can adjust the power flow among feeders and provide voltage support for power outage areas. Considering the sequential coordination of switching operation and SOP control mode selection, a multi-stage supply restoration method with SOPs is proposed for ADNs. First, the sequential energization is formulated, in which the impact of SOP control mode on restoration sequence is analyzed. By providing voltage support, the coordination of SOPs will rapidly energize the outage area and improve the voltage profile. Then, a multi-stage restoration model with SOPs is proposed, in which reconfiguration of switches and control mode selection of SOPs are coordinated in sequence to maximize the load recovery level of ADNs. Through the switching action-time mapping, secure operation is ensured during the entire supply restoration process. Finally, the effectiveness of the proposed method is validated on a modified IEEE 33-node distribution system and practical distribution networks with four-terminal SOP. Results show that the proposed method can fully exploit the potential benefits of SOPs and effectively enhance the load recovery level of ADNs.
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| 12. |
- Khodadadi, Abolfazl, et al.
(författare)
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Stochastic adaptive robust approach for day-ahead energy market bidding strategies in hydro dominated sequential electricity markets
- 2022
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier BV. - 2352-4677. ; 32
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel methodological approach for the optimal day-ahead energy market bidding behavior of a cascaded hydropower plants (HPPs) portfolio in the sequential electricity markets. The understudy markets are day-ahead energy market and manual frequency restoration reserve (mFRR) markets in both capacity and energy setups. The introduction of the mFRR capacity market ensures transmission system operators (TSOs) about the availability of energy bids in the real-time market, which acts as binding constraints in the mFRR energy markets. As a determining factor, the active-time duration of mFRR energy bids is uncertain at the time of day-ahead bidding, which is modeled as the intervals in our robust optimization, while the electricity prices are considered as the scenarios in the stochastic optimization. Hence, we have proposed a novel stochastic adaptive robust optimization to address the bidding problem in the face of uncertainties accurately. The results show a considerable improvement compared to the conventional fully-stochastic approach in the case study of Swedish cascaded hydropower plants.
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| 13. |
- Li, Wei, et al.
(författare)
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A PMU-based state estimator considering classic HVDC links under different control modes
- 2015
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 2, s. 69-82
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Tidskriftsartikel (refereegranskat)abstract
- This paper aims to develop a PMU-based state estimation algorithm that considers the presence of classic HVDC links operating under different control modes. Thus, hybrid AC/DC grid state estimation becomes feasible. In this algorithm we assume that DC link measurements can be sampled and reported at the same rate as PMU measurements, so that both AC and DC states can be estimated simultaneously in real-time. The estimation algorithm uses synchrophasors in polar coordinates, which allows angle bias detection and correction. In addition, some practical issues for the proposed state estimator are discussed, including observability and measurement redundancy, measurement noise and weightings, and angle bias correction. Finally, study cases using different power system models are carried out to show the state estimator’s performances during both steady conditions and dynamic changes. Relatively small residuals during steady conditions validate accuracy; results during dynamic changes verify the estimator’s reliability.
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| 14. |
- Mohammadi, Younes, et al.
(författare)
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An unsupervised learning schema for seeking patterns in rms voltage variations at the sub-10-minute time scale
- 2022
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 31
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes an unsupervised learning schema for seeking the patterns in rms voltage variations at the time scale between 1 s and 10 min, a rarely considered time scale in studies but could be relevant for incorrect operation of end-user equipment. The proposed framework employs a Kernel Principal Component Analysis (KPCA) followed by a k-means clustering. The schema is applied on 10-min time series with a 1-s time resolution obtained from 44 different periods of a location south of Sweden. Then, ten patterns are obtained by reconstructing the 10-min time series from each cluster center. The results of the proposed schema show a good separation of cluster centers. Moreover, some statistical power-quality indices are applied to the whole dataset, showing voltage variation between (0.5–3) V over a 10-min window. Obtaining the most suitable indices and applying them to the ten obtained cluster centers and their belonging time series shows that the existing statistical indices may not be enough to show a complete picture of the sub-10 min actual variations. This outcome shows the necessity of extracting 10-min patterns through our proposed schema besides the existing statistics to quantify the voltage variations, levels, and patterns together. Findings of this paper are: Not forgetting the sub-10-min time scale; The necessity of employing both statistics and the proposed schema; Extraction of ten typical patterns; The need for the statistics and patterns that are justified as changes in equipment connected to the grid; and compressing a huge amount of data from power-quality monitoring. The proposed schema is applied to a much less understood phenomena/disturbance type so that this work will result in general knowledge beyond the specific case study.
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| 15. |
- Mohammadi, Younes, et al.
(författare)
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Quantifying power system frequency quality and extracting typical patterns within short time scales below one hour
- 2024
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 38
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Tidskriftsartikel (refereegranskat)abstract
- This paper addresses the lack of consideration of short time scales, below one hour, such as sub-15-min and sub-1-hr, in grid codes for frequency quality analysis. These time scales are becoming increasingly important due to the flexible market-based operation of power systems as well as the rising penetration of renewable energy sources and battery energy storage systems. For this, firstly, a set of frequency-quality indices is considered, complementing established statistical indices commonly used in power-quality standards. These indices provide valuable insights for quantifying variations, events, fluctuations, and outliers specific to the discussed time scales. Among all the implemented indices, the proposed indices are based on over/under frequency events (6 indices), fast frequency rise/drop events (6 indices), and summation of positive and negative peaks (1 index), of which the 5 with the lowest thresholds are identified as the most dominant. Secondly, k-means and k-medoids clustering methods in a learning scheme are employed to identify typical patterns within the discussed time windows, in which the number of clusters is determined based on prior knowledge linked to reality. In order to clarify the frequency variations and patterns, three frequency case studies are analyzed: case 1 (sub-15-min scale, 10-s values, 6 months), case 2 (sub-1-hr scale, 10-s values, 6 months), and case 3 (sub-1-hr, 3-min values, the year 2021). Results obtained from the indices and learning methods demonstrate a full picture of the information within the windows. The maximum value of the highest frequency value minus the lowest one over the windows is about 0.35 Hz for cases 1 and 2 and 0.25 Hz for case 3. Over-frequency values (with a typical 0.1% threshold) slightly dominates under-frequency values in cases 1 and 2, while the opposite is observed in case 3. Medium fluctuations occur in 35% of windows for cases 1 and 2 and 41% for case 3. Outlier values are detected using the quartile method in 70% of windows for case 2, surpassing the other two cases. About six or seven typical patterns are also extracted using the presented learning scheme, revealing the frequency trends within the short time windows. The proposed approaches offer a simpler alternative than tracking frequency single values and also capture more comprehensive information than existing approaches that analyze the aggregated frequency values at the end of the specific time windows without considering the frequency trends. In this way, the network operators have the possibility to monitor the frequency quality and trends within short time scales using the most dominant indices and typical patterns.
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| 16. |
- Mohammadi, Younes, et al.
(författare)
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Voltage-sag source detection: Developing supervised methods and proposing a new unsupervised learning
- 2022
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 32
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Tidskriftsartikel (refereegranskat)abstract
- Recognition and analysis of voltage sags (dips) allow network operators to predict and prevent problems in real-life applications. Clearing the voltage sag source by direction detection methods is the most effective way to solve and improve the voltage sags and their related problems. However, the existing analytical methods use single or two input features as phasor-based (PB) or instantaneous-based (IB) values. Hence, their limited maximum accuracy is given at 93% and 84% when using PB features for noiseless and high-level noise signals, respectively. To increase the detection accuracy, the main contributions of this research by proposing machine learning (ML) methods include: (a) Developing nine supervised methods including support vector machine (SVM)-based, tree-based, others, and an ensemble learning of said methods, and providing a comparative analysis (b) Employing a set of PB, IB, and both PB and IB input features as noiseless and noisy; (c) Finding the best developed supervised methods by highest possible accuracy under subsets said in (b); (d) Proposing a new unsupervised method fed by both PB and IB features using a sparse principal component analysis (SPCA) applied to a k-means clustering with an internal SPCA approach. The proposed unsupervised schema does not use the upstream/downstream labels in developed supervised methods. Extensive simulations of voltage sags due to fault and transformer energizing on a Brazilian regional network show that regardless of the sag sources, input feature subset, and noise levels, the random forest (RF) models yield the best performance so that noiseless-RF (99.84%) using both PB and IB features is the most effective one. The proposed unsupervised method outcomes an overall accuracy of 99.17%-noiseless and about 90% for high-level noises. This performance is higher than analytical methods, very close to SVM-based supervised methods, and uses no predefined labels. Moreover, the results of Slovenian field measurements confirm the effectiveness of the best-developed supervised methods and the proposed unsupervised learning.
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| 17. |
- Mousavi, Milad, et al.
(författare)
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A contract-based trading of power flexibility between a variable renewable energy producer and an electricity retailer
- 2023
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 34
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Tidskriftsartikel (refereegranskat)abstract
- Variable renewable energy producers and electricity retailers encounter several uncertainties in their decision-making problems, such as intermittency of renewable energy sources, variability of consumption, and market price volatility. To cope with these uncertainties, this paper presents a new contract-based trading mechanism of power flexibility (FlexCon) between two parties, a variable renewable energy producer and an electricity retailer. The proposed mechanism is managed by a new entity, named FlexCon operator, to oversee the energy and financial trades through the contract and coordinate the transactions with the system operator. Through the FlexCon, the parties are able to exchange their energy imbalances as a source of power flexibility to alleviate the negative impacts of uncertainties in their decision-making problems. To this end, two two-stage stochastic linear problems are introduced from each party’s point of view. In the first stage, the variable renewable energy producer and the electricity retailer submit their bids to sell and purchase in the day-ahead market, respectively. Following the day-ahead market clearing, closer to the delivery time, the parties submit their decisions on the contract to the introduced FlexCon operator. The operator allocates possible power flexibility transactions based on the surpluses or shortages of the parties. Assuming that the imbalances are not completely resolved with the FlexCon, the remaining deviations are settled in the balancing market. The parties’ decisions related to the balancing market and the FlexCon are modeled in the second stage of the stochastic problem. The uncertainties associated with prices, renewable generation, electricity consumption, and the maximum exchangeable power flexibility through the FlexCon are considered via scenarios. Meanwhile, the profit risk is considered by the Conditional Value at Risk measure. The numerical results show that FlexCon effectively diminishes the impacts of uncertainties on the parties’ profit.
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| 18. |
- Mulenga, Enock, et al.
(författare)
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Multiple distribution networks hosting capacity assessment using a stochastic approach
- 2023
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier Ltd. - 2352-4677. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- About 15 000-customers are connected to the individual secondary distribution networks supplied through 48-medium voltage 10 kV radial feeders. The hosting capacity assessment uses the end-customer voltage magnitude rise and transformer thermal overload. The hosting capacity is estimated by applying the “stochastic mixed aleatory-epistemic method” to determine the voltage magnitude rise and load flow with solar PV. The minimum power consumption is compared with the solar PV power infeed through the individual transformers. The hosting capacity estimation is done for three-phase connected solar PV sizes from 3 to 18 kW. At moderate PV penetration (25%–50%), the results showed that overvoltage would limit the hosting capacity more often than overload, but it becomes an issue only for LV networks studied with more than 8-customers. Considering all LV networks, most of the customers could install 6 kWp. Even when installing PV systems of 18 kWp (about twice the average size today and about the maximum area of a typical residential roof), two-thirds of houses would not need an upgrade to withstand SS-EN 50160 voltage limits. The latter customers can connect solar PV units with 18 kWp size without overvoltage or overload issues.
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| 19. |
- Nammouchi, Amal, et al.
(författare)
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Robust opportunistic optimal energy management of a mixed microgrid under asymmetrical uncertainties
- 2023
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- Energy management within microgrids under the presence of large number of renewables such as photovoltaics is complicated due to uncertainties involved. Randomness in energy production and consumption make both the prediction and optimality of exchanges challenging. In this paper, we evaluate the impact of uncertainties on optimality of different robust energy exchange strategies. To address the problem, we present AIROBE, a data-driven system that uses machine-learning-based predictions of energy supply and demand as input to calculate robust energy exchange schedules using a multiband robust optimization approach to protect from deviations. AIROBE allows the decision maker to tradeoff robustness with stability of the system and energy costs. Our evaluation shows, how AIROBE can deal effectively with asymmetric deviations and how better prediction methods can reduce both the operational cost while at the same time may lead to increased operational stability of the system.
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| 20. |
- Nazari, Mohammad Hassan, et al.
(författare)
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An economy-oriented DG-based scheme for reliability improvement and loss reduction of active distribution network based on game-theoretic sharing strategy
- 2021
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Ingår i: Sustainable Energy, Grids and Networks. - : ELSEVIER. - 2352-4677. ; 27
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a techno-economic strategy for reliability improvement and loss reduction in active distribution networks and microgrids including distributed generations (DGs). This approach is a theoretical method stand on the determination of locational marginal price in each bus including DGs. In this method, each DG is a player of game theory considering its effect on mitigated loss and enhanced reliability. In this proposed approach, each player receives an economic incentive in case of incremental price using a fair method based on the game theory. To illustrate, DGs that vary their generations with the desired objectives of the network will receive incentives in terms of incremental price in selling energy and obtaining more benefits. Moreover, to attain a feasible realistic structure, the uncertainties of loads are studied. In addition, as an approach for controlling the operation of the network, the suggested approach should supervise the contribution of DGs in incentives allocation which leads to meeting each network's goals based on their contributions in the pricing approach. Validation of the proposed method is performed based on testing the Taiwan Power Company (TPC) network. The significant outcomes show that the lines loss of the network are reduced by 56% and the reliability improvement percentage is 14%.
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| 21. |
- Rahme, Sandy Youssef, et al.
(författare)
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Adaptive sliding mode control for instability compensation in DC microgrids due to EV charging infrastructure
- 2023
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Ingår i: Sustainable Energy, Grids and Networks. - : ELSEVIER. - 2352-4677. ; 35
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Tidskriftsartikel (refereegranskat)abstract
- The electric vehicle (EV) chargers with the battery voltage/current regulated starts behaving as constant power loads. Therefore, the connection of EV chargers in dc microgrid reduces the stability margin of the system which can destabilize a dc microgrid. Further, the limit on charging power supplied by the EV charger to the battery increases the charging time of the battery. The main aim of this paper is to compensate the instability caused due to EV chargers in a dc microgrid including renewable energy sources like solar photovoltaic (PV) sources which are interfaced to dc-bus using dc-dc boost converters. For stabilization of this system, an adaptive sliding mode control (ASMC) is synthesized for dc-dc boost converters feeding constant power load. The proposed controller modifies its gain in order to maintain sufficient stability margin during large step variation in load demand. The adaptive variation ensures a high robustness against wide changes of the charging power demand and does not require any prior knowledge about the bounds of the system. Further, the stability analysis of the proposed ASMC using Lyapunov method guarantees the finite time convergence of sliding surface and asymptotic convergences of converter state variables. The efficacy of the proposed controller is validated with the help of results captured using Controller Hardware-in-the-Loop (CHIL) and experimental setup. These results show the effectiveness of practical implementation of the proposed controller.
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| 22. |
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| 23. |
- Tkachuk, Roman-Valentyn, et al.
(författare)
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Towards Efficient Privacy and Trust in Decentralized Blockchain-Based Peer-to-Peer Renewable Energy Marketplace
- 2023
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 35
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Tidskriftsartikel (refereegranskat)abstract
- Renewable energy sources are becoming increasingly important as a substitute for fossil energy production. However, distributed renewable energy production faces several challenges regarding trading and management, such as inflexible pricing models and inaccurate green consumption information. A decentralized peer-to-peer (P2P) electricity marketplace may address these challenges. It enables prosumers to market their self-produced electricity. However, such a marketplace needs to guarantee that the transactions follow market rules and government regulations, cannot be manipulated, and are consistent with the generated electricity. One of the ways to provide these guarantees is to leverage blockchain technology.This work describes a decentralized blockchain-based P2P energy marketplace addressing privacy, trust, and governance issues. It uses a private permissioned blockchain Hyperledger Fabric (HF) and its smart contracts to perform energy trading settlements. The suggested P2P marketplace includes a particular regulator actor acting as a governmental representative overseeing marketplace operations. In this way, the suggested P2P marketplace can address the governance issues needed in electricity marketplaces. Further, the proposed marketplace ensures actors’ data privacy by employing HF’s private data collections while preserving the integrity and auditability of all operations. We present an in-depth performance evaluation and provide insights into the security and privacy challenges emerging from such a marketplace. The results demonstrate that partial centralization by the applied regulator does not limit the P2P energy trade settlement execution. Blockchain technology allows for automated marketplace operations enabling better incentives for prosumer electricity production. Finally, the suggested marketplace preserves the user’s privacy when P2P energy trade settlements are conducted.
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| 24. |
- Wu, Yiming, et al.
(författare)
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Adaptive data link configuration for WAMC applications using a Stateful Data Delivery Service platform
- 2016
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Ingår i: Sustainable Energy, Grids and Networks. - : Elsevier. - 2352-4677. ; 6, s. 166-175
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Tidskriftsartikel (refereegranskat)abstract
- Wide Area Monitoring and Control (WAMC) applications provide, among other things, stability control to power systems by using global measurements. However, these measurements suffer unavoidable Quality of Service (QoS) problems, such as delay, during the transmission through a wide area communication network. Such delays potentially lead to failure of the control application. To overcome these effects, mechanisms that provide robustness to QoS problems for control applications and configuration of communication networks to optimize QoS performance have been proposed by several researchers. To optimize utilization of the communication infrastructure and to adapt to variations in QoS, applications can benefit from an interface to request and obtain QoS information from a managed communication infrastructure. To meet this need, a novel Stateful Data Delivery Service (SDDS) for WAMC applications is proposed in this paper. The SDDS monitors the QoS performance online and provides feedback to one or more WAMC applications. To increase reliability of the applications, the SDDS also provides adaptive data link configuration services. By using online QoS measurements and multiple data sources, the SDDS platform can provide a WAMC application with data fulfilling its requirements. To prove the concept, a case study has been performed and the results of this study show that the application using the SDDS can keep a benchmark power system stable even when original data link QoS performance does not meet the application's requirements. The paper also contains a presentation of the SDDS prototype platform under development as a part of the ongoing research.
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