| 1. |
- Armendariz, Mikel, et al.
(författare)
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A Method to Design Optimal Communication Architectures in Advanced Metering Infrastructures
- 2017
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Ingår i: IET Generation, Transmission & Distribution. - : IET Digital Library. - 1751-8687 .- 1751-8695. ; 11:2, s. 339-346
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Tidskriftsartikel (refereegranskat)abstract
- This paper proposes a method to determine the optimal communication architecture in advance metering infrastructures (AMI). The method starts by indicating suitable groups of meters that share similar characteristics such as distance to the secondary substation and mutual proximity. Then it connects each group of meters to the AMI-Head End through a communication architecture formed by wireless and Power Line Communication (PLC) technologies. The optimality criterion takes into account the Capital Expenditures (CAPEX), Operational Expenditures (OPEX) and the Quality of Service (QoS) in the communication architecture. The method is tested on a LV network based on real utility data provided by EU FP7 DISCERN project partners. These tests show that the method is consistent with planning foresight and can be useful to assist in the AMI communication architecture designing process.
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| 2. |
- Armendariz, Mikel, et al.
(författare)
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Strategies to improve the voltage quality in active low-voltage distribution networks using DSO's assets
- 2017
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Ingår i: IET Generation, Transmission & Distribution. - : IEEE. - 1751-8687 .- 1751-8695. ; 11:1, s. 73-81
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Tidskriftsartikel (refereegranskat)abstract
- This study addresses the problem of voltage variations in active low-voltage distribution networks caused by distributed photovoltaic (PV) generation. Three strategies based on model predictive control (MPC) are introduced to flatten the voltage profile in a cost-optimal way. The compared strategies are the business as usual approach that manipulates a controllable on-load tap changer at the primary substation, the problematic feeder control strategy (CS) that adds an additional degree of freedom by controlling the critical secondary substations (SSs), and finally the compensation strategy, which controls the primary substation and compensates the non-critical SSs. A sensitivity analysis on the CSs has been conducted comparing the voltage variation reduction and the asset utilization with regard to the accuracy of the prediction models and the forecasted disturbance data. The results show that better (and more costly) characterisation of these parameters only provide a marginal improvement in the reduction of the voltage variations due to the restriction caused by the heavy tap change penalisation. Moreover, the tested case-study shows that the problematic feeder CS outperforms the compensation strategy in terms of larger voltage variation reduction for similar asset utilisation.
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| 3. |
- Astero, Poria, 1984-, et al.
(författare)
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Multi-agent transactive energy management system considering high levels of renewable energy source and electric vehicles
- 2017
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Ingår i: IET Generation, Transmission & Distribution. - : The IET: The Institution of Engineering and Technology. - 1751-8687 .- 1751-8695. ; 11:15, s. 3713-3721
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Tidskriftsartikel (refereegranskat)abstract
- The future smart grids (SGs) consist of considerable amount of renewable energy sources (RESs), electrical vehicles (EVs), and energy storage systems (ESSs). The uncertainties associated with EVs and uncontrollable nature of RESs have magnified voltage stability challenges and the importance of an effective energy management system (EMS) in SGs as a practical solution. This study presents a multi-agent transactive energy management system (TEMS) to control demand and supply in the presence of high levels of RESs and EVs, and maximises profit of each participant in addition to satisfying voltage regulation constraints. For this purpose, a real-time pricing is considered based on Cournot oligopoly competition model for demand and merit order effect for production to compensate RESs' fluctuations in real time by an indirect control method. Simulations are conducted in the modified IEEE 37-bus test system with 1141 customers, 670 EVs, two solar plants, four wind turbines, and one ESS. The results show that the proposed multi-agent TEMS can indirectly control EVs, elastic loads, and ESSs to balance the RESs oscillation, minimise customers cost, and regulate voltage in a real-time manner.
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| 4. |
- Babazadeh, Davood, et al.
(författare)
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Real-Time Estimation of AC-Grid Short Circuit Capacity for HVDC Control Application
- 2016
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Ingår i: IET Generation, Transmission & Distribution. - : IET. - 1751-8687 .- 1751-8695.
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Tidskriftsartikel (refereegranskat)abstract
- Being able to estimate the AC grid strength using Short Circuit Capacity (SCC) fromthe perspective of a connected HVDC station allows adjustment of converter control parameters orto select the converter’s operational control mode. The short circuit capacity can be calculated byestimation of the grid’s impedance and its equivalent voltage. This paper presents the operationaland practical challenges in real-time implementation of the grid estimation algorithms especiallyfor HVDC applications. This paper shows that the Recursive Least Square (RLS) algorithm can bevery efficiently used for the real-time estimation of SCC. This technique forms a regression prob-lem using algebraic complex equations with an objective to minimize the error between estimatedand measured parameters. The algorithm has been reformulated and simplified to make it non-complex without the use of matrices, in order to facilitate further implementation on an industrialreal-time controller. The performance of the real-time implementation has been evaluated usinga HIL platform. A sensitivity analysis has been also carriedout to study the impact of differentparameters and operational conditions on the performance of the estimation algorithm. Finally, theactual application of real-time SCC estimation for the HVDCsystems has been demonstrated.
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| 5. |
- Balram, Pavan, 1986, et al.
(författare)
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Demonstration of Voltage Control in a Real Distribution System using Model Predictive Control
- 2017
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Ingår i: IET Generation, Transmission and Distribution. - : Institution of Engineering and Technology (IET). - 1751-8687 .- 1751-8695. ; 11:16, s. 3922-3929
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the results from field tests that were carried out with the aim of verifying the performance of a model predictive control-based voltage controller. A voltage source converter capable of producing or consuming 4 MVAr was used as the reactive power source, which was able to influence the voltage magnitude at a remote bus within a real distribution system in Gothenburg, Sweden. The voltage controller is designed to maintain the remote bus voltage within a pre-defined range while respecting the reactive power output capability of the voltage source converter and an objective of minimum changes to the reference value of its local reactive power controller. Results from the field tests demonstrate that the voltage controller was able to successfully regulate the voltage even with significant errors in the state-space prediction model. An important lesson learned from the field test is that a smoothened voltage measurement feedback is critical to a satisfactory functioning of the controller. Furthermore, it is recommended to design the voltage controller to observe an initial delay, before it is activated for bus voltage control- this would deter it from unnecessarily reacting at the very instant it is brought online.
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| 6. |
- Becerra Garcia, Marley, et al.
(författare)
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Lightning striking distance of complex structures
- 2008
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Ingår i: IET Generation, Transmission & Distribution. - : Institution of Engineering and Technology (IET). - 1751-8687 .- 1751-8695. ; 2:1, s. 131-138
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Tidskriftsartikel (refereegranskat)abstract
- Traditionally, the location of lightning strike points has been determined byusing the rolling sphere method, but recently the collection volumemethod (CVM) has also been proposed for the placement ofair terminals on complex structures. Both these methods are empiricalin nature and a more advanced model based on physicsof discharges is needed to improve the state of affairs.This model is used to evaluate the striking distance fromcorners and air terminals on actual buildings and the resultsare qualitatively compared with the predictions of the rolling spheremethod and the CVM. The results show that the strikingdistance not only depends upon the prospective return stroke currentand the geometry of the building, but also on thelateral position of the downward leader with respect to thestrike point. A further analysis is performed to qualitatively comparethe lightning attraction zones obtained with the CVM and theleader inception zones obtained for a building with and withoutair terminals. The obtained results suggest that the collection volumeconcept overestimates the protection areas of air terminals placed oncomplex structures, bringing serious doubts on the validity of this method.
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| 7. |
- Beerten, Jef, et al.
(författare)
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Guest editorial
- 2016
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Ingår i: IET Generation, Transmission & Distribution. - : Institution of Engineering and Technology. - 1751-8687 .- 1751-8695. ; 10:6, s. 1313-1314
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Blaauwbroek, Niels, et al.
(författare)
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Interfacing solutions for power hardware-inthe- loop simulations of distribution feeders for testing monitoring and control applications
- 2017
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Ingår i: IET Generation, Transmission & Distribution. - : IET Digital Library. - 1751-8687 .- 1751-8695.
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Tidskriftsartikel (refereegranskat)abstract
- The need for advanced monitoring and control applications (MCAs) in future distribution networks calls for highly accurate and fully integrated simulation solutions for the purpose of performance assessment of these MCAs. Offline simulation using models of the power system, measurement equipment, local controllers and the information and communication infrastructure do not always resemble reality accurate enough. Therefore, power hardware-in-the-loop (PHIL) simulations are considered a cost-effective approach to overcome these challenges. This study presents the design of a PHIL-interface that allows to integrate a physical low-voltage feeder within a larger real-time simulated distribution network. Using the combination of the physical network and the larger simulated network, MCAs can be tested for scalability as well as accuracy. A data acquisition and processing system is presented that acquires all the true system states of both the physical feeder and the real-time simulated network, such that the MCAs can be verified in real-time. The functioning of the PHIL-interface is validated using practical results and illustrated using a test case for the performance assessment of a branch current state estimation algorithm.
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| 9. |
- Brolin, Magnus, et al.
(författare)
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Controlling a retailer's short-term financial risk exposure using demand response
- 2019
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Ingår i: IET Generation, Transmission & Distribution. - : Institution of Engineering and Technology. - 1751-8687 .- 1751-8695. ; 13:22, s. 5160-5170
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Tidskriftsartikel (refereegranskat)abstract
- The transition of the electric power system to reach sustainability goals leads to new market conditions with larger uncertainties. This constitutes new challenges and opportunities for new as well as for existing market players such as retailers. In a future more volatile and unpredictable market, financial risk management becomes an important element for such actors in order to achieve viable businesses. Different instruments can be applied for this purpose, where demand response can contribute in the short-term to manage risks related to price variations and imbalance costs. This study contributes to the enhancement of retailer's businesses by presenting a stochastic optimisation model exploring the possibility to apply demand response to control financial risk exposure. The model considers trading and demand response scheduling for different customer clusters, generating optimal trading volumes for day-ahead markets while also considering the possibility to trade intra-day. The optimisation considers uncertainties in prices and loads as well as imbalance settlement costs. Risk management is integrated into the model by applying conditional value-at-risk as risk measures. The developed model has also been applied in a case study with data from the Swedish and Nordic electricity market together with simulated load profiles for different customer clusters.
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| 10. |
- Chamorro, Harold R., et al.
(författare)
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Non-synchronous generation impact on power systems coherency
- 2016
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Ingår i: IET Generation, Transmission & Distribution. - : Institution of Engineering and Technology. - 1751-8687 .- 1751-8695. ; 10:10, s. 2443-2453
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Tidskriftsartikel (refereegranskat)abstract
- The increasing integration of renewables into the grid based on power electronics converters interfaces is affecting the power systems dynamics, requiring effective monitoring and visualisation to provide appropriate assessment during extreme events. The coherent group identification in power systems is of importance for dynamic studies and transmission capability improvement. This study analyses the coherency based on the mode shapes, the application of the Koopman mode analysis (KMA) and a Prony analysis (PA) on-line variation for the identification of coherent groups in power systems. KMA and PA use the voltage angle measurements obtained from simulation. The clustering of the coherent groups are evaluated in two test systems. The coherency methods are also evaluated taking into account the impact of a large gradual scale inclusion of non-synchronous generation under different penetration level cases. From the comparison and visualisation of the different methods it is possible to observe the impact of the large inclusion of non-synchronous generation on the coherency.
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