| 1. |
- Mai, Tam T., et al.
(författare)
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An overview of grid-edge control with the digital transformation
- 2021
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Ingår i: Electrical Engineering. - : Springer Science and Business Media LLC. - 1432-0487 .- 0948-7921. ; 103:4, s. 1989-2007
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Tidskriftsartikel (refereegranskat)abstract
- Distribution networks are evolving to become more responsive with increasing integration of distributed energy resources (DERs) and digital transformation at the grid edges. This evolution imposes many challenges to the operation of the network, which then calls for new control and operation paradigms. Among others, a so-called grid-edge control is emerging to harmonise the coexistence of the grid control system and DER’s autonomous control. This paper provides a comprehensive overview of the grid-edge control with various control architectures, layers, and strategies. The challenges and opportunities for such an approach at the grid edge with the integration of DERs and digital transformation are summarised. The potential solutions to support the network operation by using the inherent controllability of DER and the availability of the digital transformation at the grid edges are discussed.
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| 2. |
- Nguyen, Anh, et al.
(författare)
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Wind Power in Power Markets: Opportunities and Challenges
- 2007
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Ingår i: Nordic Wind Power Conference, 1-2 November 2007, Roskilde, Denmark.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper provides a comprehensive review of the opportunities and challenges from trading of wind power in power markets. The opportunities are the low operating costs, government incentive/subsidy program, reduction of market price, reduction of carbon dioxide emission, reduction of network loss, etc. The challenges would be technical requirement for power system integration, high investment cost, increased requirement on regulation power due to wind forecast error, more price volatile, more market competition for other generations, etc. The opportunities and challenges are discussed from different market players’ perspectives. Some suggestions for possible measures to overcome those challenges are presented.
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| 3. |
- Srivastava, Ankur, 1989, et al.
(författare)
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Development of a DSO Support Tool for Congestion Forecast
- 2021
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Ingår i: IET Generation, Transmission and Distribution. - : Institution of Engineering and Technology (IET). - 1751-8687 .- 1751-8695. ; 15:23, s. 3345-3359
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel DSO support tool with visualisation capability for forecasting network congestion in distribution systems with a high level of renewables. To incorporate the uncertainties in the distribution systems, the probabilistic power flow framework has been utilised. An advanced photovoltaic production forecast based on sky images and a load forecast using an artificial neural network is used as the input to the tool. In addition, advanced load models and operating modes of photovoltaic inverters have been incorporated into the tool. The tool has been applied in case studies to perform congestion forecasts for two real distribution systems to validate its usability and scalability. The results from case studies demonstrated that the tool performs satisfactorily for both small and large networks and is able to visualise the cumulative probabilities of nodes voltage deviation and network components (branches and transformers) congestion for a variety of forecast horizons as desired by the DSO. The results have also shown that explicit inclusion of load-voltage dependency models would improve the accuracy of the congestion forecast. For demonstrating the applicability of the tool, it has been integrated into an existing distribution management system via the IoT platform of a DMS vendor, Atos Worldgrid.
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| 4. |
- Wang, Feng, 1975, et al.
(författare)
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An extended OPF incorporating multi-terminal VSC-HVDC and its application on transmission loss evaluation
- 2013
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Ingår i: 2013 IEEE Grenoble Conference PowerTech, POWERTECH 2013. - 9781467356695
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Konferensbidrag (refereegranskat)abstract
- This paper proposes an extension of the traditional ac Optimal Power Flow (OPF) model to incorporate the Voltage Source Converter based Multi-terminal High Voltage Direct Current system (VSC-MTDC). In the extended OPF model, the detailed VSC-MTDC system model is included, and the key technical limits of VSC (e.g., the maximum VSC valve current and the maximum dc voltage) are used as the operating constraints of the VSC-MTDC system. The extended OPF model is applied to a case study using the Nordic 32-bus system to evaluate the contribution of the embedded VSC-MTDC system on the overall system loss reduction. The study results show that the overall system loss of an ac transmission grid is not necessarily reduced by embedding a VSC-MTDC system into it. The reduction of the system loss by embedded VSC-MTDC system depends on their configuration and location, and the VSC station loss ratio as well.
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| 5. |
- Agathokleous, Christos, 1993, et al.
(författare)
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Stochastic Operation Scheduling Model for a Swedish Prosumer with PV and BESS in Nordic Day-Ahead Electricity Market
- 2019
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Ingår i: 2019 IEEE Milan PowerTech, PowerTech 2019.
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Konferensbidrag (refereegranskat)abstract
- In this paper, an optimal stochastic operation scheduling model is proposed for a prosumer owning photovoltaic (PV) facility coupled with a Battery Energy Storage System (BESS). The objective of the model is to maximize the prosumer’s expected profits. A two-stage stochastic mixed-integer nonlinear optimization (SMINLP) approach is used to cope with the parameters’ uncertainties. Artificial Neural Networks (ANN) are used to forecast the markets’ prices and the standard scenario reduction algorithms are applied to handle the computational tractability of the problem. The model is applied to a case study using data from the Nordic electricity markets and historical PV production data from the Chalmers University of Technology campus, considering a scaled up 5MWp power capacity. The results show that the proposed approach could increase the revenue for the prosumer by up to 11.6% as compared to the case without any strategy. Furthermore, the sensitivity analysis of BESS’s size on the expected profit shows that increasing BESS size could lead to an increase in the net profits.
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| 6. |
- Alghamdi, Baheej, et al.
(författare)
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A Comparative Study on SVC and STATCOM in Dynamic Voltage Stability Improvement of a System with Different Load Characteristics
- 2017
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Ingår i: 2017 SAUDI ARABIA SMART GRID CONFERENCE (SASG). - 9781538618769
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Konferensbidrag (refereegranskat)abstract
- This paper presents a comparison between the dynamic performance of Static Var Compensators (SVC) and Static Synchronous Compensators (STATCOM) in improving the voltage stability of the system and reducing the post disturbance voltage recovery time. The dynamic simulation has been done on the Nordic-32 test system which mimics the characteristics of the Swedish transmission system. The simulation has been carried out using a time-domain simulation software called PSS/E. The simulation has been done while taking into account different load characteristics including induction motor loads which are prevalent in the Swedish power grid. A methodology for sizing and placement of the SVC and STATCOM has been proposed to mitigate the voltage instability of the system. It has been found that STATCOMs have shown superior performance over SVCs in improving the post-disturbance voltage recovery time and the voltage stability of the system. It has been found that the post disturbance voltage recovery time was reduced down by 60% for the case with STATCOM while for the case with SVC, the voltage recovery time was reduced down by 26% for the same capacitive rating as that of the STATCOM(1).
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| 7. |
- Alghamdi, Baheej, et al.
(författare)
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A comparative study on SVC and STATOCM in dynamic voltage stability improvement of a system with different load characteristics
- 2018
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Ingår i: 2017 Saudi Arabia Smart Grid Conference, SASG 2017. ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- This paper presents a comparison between the dynamic performance of Static Var Compensators (SVC) and Static Synchronous Compensators (STATCOM) in improving the voltage stability of the system and reducing the post disturbance voltage recovery time. The dynamic simulation has been done on the Nordic-32 test system which mimics the characteristics of the Swedish transmission system. The simulation has been carried out using a time-domain simulation software called PSS/E. The simulation has been done while taking into account different load characteristics including induction motor loads which are prevalent in the Swedish power grid. A methodology for sizing and placement of the SVC and STATCOM has been proposed to mitigate the voltage instability of the system. It has been found that STATCOMs have shown superior performance over SVCs in improving the post-disturbance voltage recovery time and the voltage stability of the system. It has been found that the post-disturbance voltage recovery time was reduced down by 60% for the case with STATCOM while for the case with SVC, the voltage recovery time was reduced down by 26% for the same capacitive rating as that of the STATCOM1.
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| 8. |
- Alghamdi, Baheej, 1985, et al.
(författare)
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Investigation of Impacts of Solar PV on Transmission System Voltage Stability Considering Load Characteristics and Protection
- 2017
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Ingår i: 7th International Workshop on the Integration of Solar Power into Power Systems, 24-25 October 2017, Berlin, Germany.
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Konferensbidrag (refereegranskat)abstract
- This paper presents an investigation on possible effects of large scale integration of solar photovoltaics (PVs) on the voltage stability of the transmission grid. The time-domain simulation approach has been used in a case study using the Nordic-32 test system which approximately represents the Swedish transmission system. The simulation study has been carried out in PSS/E for different penetration levels of solar PVs and solar irradiance conditions considering different load characteristics and detailed model of distance relays. The main question to be addressed by the study is how the location and size of the PV plants, load characteristics and the transmission system distance protection can adversely affect the post-disturbance voltage recovery time and thereby the overall voltage stability. It has been found that the post-disturbance voltage recovery time increased by 100% with 30% PV penetration. Another interesting finding is that in the case of high PV penetration, the PV plants can either support or adversely affect the voltage stability of the system, depending on changes in the irradiance and the load level during the day. That is that during periods when the PV plants produce their rated active power, the system was more prone to voltage instability after being subjected to a disturbance compared to the periods where the PV plants produce only reactive power which supports the voltage stability.
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| 9. |
- Alvarez Quispe, Erik Fransisco, et al.
(författare)
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Values and Impacts of Incorporating Local Flexibility Services in Transmission Expansion Planning
- 2022
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Ingår i: Electric Power Systems Research. - : Elsevier BV. - 0378-7796. ; 212
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a cost-based TSO-DSO coordination model to quantify the value of local flexibility services and analyze its impact on the transmission grid expansion and the system operation. Flexibility is provided to the DC power flow transmission grid model by microgrids within the integrated AC power flow distribution grid model. The model's objective is to minimize the overall cost of transmission investments and procured flexibility and is achieved using a bilevel optimization approach where the power exchanges on all connected grid interfaces are controlled. Case studies using a combined test system of the IEEE RTS-96 transmission network interfacing multiple 33-bus distribution grids were performed to validate the model and assess the values and impacts of local flexibility on the transmission system expansion. The results showed that the proposed model modified the investment plan and dispatch of flexibility resources reducing the investment and operation cost of the transmission system.
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| 10. |
- Antoniadou-Plytaria, Kyriaki, 1989, et al.
(författare)
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Chalmers Campus as a Testbed for Intelligent Grids and Local Energy Systems
- 2019
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Ingår i: IEEE International Conference on Smart Energy Systems and Technologies (SEST). - 9781728111568
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Konferensbidrag (refereegranskat)abstract
- This paper presents an overview of a testbed for intelligent distribution grids, local energy systems, and energy flexible buildings, which is being developed at the campus of Chalmers University of Technology in Gothenburg, Sweden. It describes the test sites, the functionalities, and the planned demonstration activities within the scope of on-going research projects. The proposed demonstrations include a local energy market platform, energy management solutions for microgrids and smart buildings, as well as voltage control in distribution grids. The paper aims to show how the physical energy supply systems of the university are being adapted to integrate the communication and control set-ups that provide the technical requirements for smart grid interoperability. As an example, the on-site implementation of remote battery control is presented, where initial results show the feasibility and potential benefits of the external control. Finally, challenges and lessons learned during the development of the testbed are highlighted.
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