• Utilization of a system-level approach and systems engineering in analyzing technologi-cal solutions in the distribution network environment
The results of this work can be used by the DSOs to identify the opportunities of using LVDC in electricity distribution. The results can also be used to determine any existing obstacles or factors that have a high impact on the potential but somehow restrict the use of LVDC, which otherwise would seem profitable. This serves the bodies in the definition of regulations, laws, and standards, both nationally and internationally. Recognition of the opportunities of LVDC can have a major impact on the readiness to tackle the coming challenges and provide the required flexibility and advanced services. Therefore, the results of this work offer tools for the strategic development of the network from the perspective of an alternative technological solution.
7.2 Future work
The work is related to a novel technological solution, which has proven to have the potential in industrial use. At present, there are some advancements from research to practice and even com-mercial utilization, but no single DSO considers and invests in LVDC as a routine solution for supplying residential customers. This is understandable because of the nature of the distribution business. What is still needed to enable the more widespread utilization is the development of standards, commercial products, tools for planning, case studies, and training. Demand is also needed for the products, but before this, it is necessary that the requirements for the products are clear. These requirements are different depending on where LVDC is used. For an LVDC investment, it has to be possible that it is assessed and can be put into practice similarly to any other network investment without a consecutive piloting notion. Owing to the novelty of LVDC, there will be many practical issues in different cases that have to be solved individually. In the course of the research, it has been found that only the practical implementation and assessment according to the valid requirements will reveal the specific issues in detail. There is a need for optimization and research & development within many related topics, such as control, network planning, ICT, EMI, converter design, and components, and most importantly, there is a need to manage the whole process of utilization. In other words, systems engineering is crucial for the optimal result. Vice versa, the risk of getting negative experiences is high. From the per-spective of this work, the immaturity aspects are important (but not fundamental) because they can have an influence on the competitiveness. The main point, instead, is that the concept has been proven to work and can therefore be a true supplementary technology for the long-term network development.
The objective of the work was to develop a framework so that the DSOs could have an insight into whether the LVDC technology could be used in the future distribution. In that sense, this doctoral dissertation is an initiative for the future work that applies and also supplements the presented framework with the local knowledge and details. Especially the aspects related to the operating environment are based on the expertise of the locals, and therefore, the cases and examples presented in this work are not and cannot be comprehensive. Instead, by using the findings of the work, it is possible to recognize the key factors within the LVDC concept and operating environment to be able to proceed to the details. What still remains to be done is the exact assessment of the potential in different cases with accurate data that often are
obtain-7.2 Future work 103
• Utilization of a system-level approach and systems engineering in analyzing technologi-cal solutions in the distribution network environment
The results of this work can be used by the DSOs to identify the opportunities of using LVDC in electricity distribution. The results can also be used to determine any existing obstacles or factors that have a high impact on the potential but somehow restrict the use of LVDC, which otherwise would seem profitable. This serves the bodies in the definition of regulations, laws, and standards, both nationally and internationally. Recognition of the opportunities of LVDC can have a major impact on the readiness to tackle the coming challenges and provide the required flexibility and advanced services. Therefore, the results of this work offer tools for the strategic development of the network from the perspective of an alternative technological solution.
7.2 Future work
The work is related to a novel technological solution, which has proven to have the potential in industrial use. At present, there are some advancements from research to practice and even com-mercial utilization, but no single DSO considers and invests in LVDC as a routine solution for supplying residential customers. This is understandable because of the nature of the distribution business. What is still needed to enable the more widespread utilization is the development of standards, commercial products, tools for planning, case studies, and training. Demand is also needed for the products, but before this, it is necessary that the requirements for the products are clear. These requirements are different depending on where LVDC is used. For an LVDC investment, it has to be possible that it is assessed and can be put into practice similarly to any other network investment without a consecutive piloting notion. Owing to the novelty of LVDC, there will be many practical issues in different cases that have to be solved individually. In the course of the research, it has been found that only the practical implementation and assessment according to the valid requirements will reveal the specific issues in detail. There is a need for optimization and research & development within many related topics, such as control, network planning, ICT, EMI, converter design, and components, and most importantly, there is a need to manage the whole process of utilization. In other words, systems engineering is crucial for the optimal result. Vice versa, the risk of getting negative experiences is high. From the per-spective of this work, the immaturity aspects are important (but not fundamental) because they can have an influence on the competitiveness. The main point, instead, is that the concept has been proven to work and can therefore be a true supplementary technology for the long-term network development.
The objective of the work was to develop a framework so that the DSOs could have an insight into whether the LVDC technology could be used in the future distribution. In that sense, this doctoral dissertation is an initiative for the future work that applies and also supplements the presented framework with the local knowledge and details. Especially the aspects related to the operating environment are based on the expertise of the locals, and therefore, the cases and examples presented in this work are not and cannot be comprehensive. Instead, by using the findings of the work, it is possible to recognize the key factors within the LVDC concept and operating environment to be able to proceed to the details. What still remains to be done is the exact assessment of the potential in different cases with accurate data that often are
obtain-104 7 Conclusions
able only by local parties involved in the operation. That work, however, is often part of the companies’ internal activities.
In the course of writing, the following questions were recognized to be pivotal from the per-spective of network development and the potential of LVDC distribution, and could be topics of future work:
• Transition to DC: How is it done over time as part of network development after the strate-gic decision has been made? What are the first targets and schedule for the investments?
How does the use of LVDC affect the overall network development?
• Opportunities of MVDC: Does it have the potential, and if yes, what kinds of mutual impacts would there be between the utilization of MVDC and LVDC?
• Use of DC in buildings and its effect on the potential of LVDC: If DC were used in buildings, solely or together with AC, how would that change the competitiveness of LVDC?
• Self-sufficient (partially or completely) communities and microgrids: What are the pos-sible mutual impacts of microgrids and LVDC, considering especially those parts of the rural networks that are challenging, for instance long lateral aerial lines with only a few customers, network parts having customers with only occasional consumption, and tar-gets vulnerable to environmental conditions?
104 7 Conclusions
able only by local parties involved in the operation. That work, however, is often part of the companies’ internal activities.
In the course of writing, the following questions were recognized to be pivotal from the per-spective of network development and the potential of LVDC distribution, and could be topics of future work:
• Transition to DC: How is it done over time as part of network development after the strate-gic decision has been made? What are the first targets and schedule for the investments?
How does the use of LVDC affect the overall network development?
• Opportunities of MVDC: Does it have the potential, and if yes, what kinds of mutual impacts would there be between the utilization of MVDC and LVDC?
• Use of DC in buildings and its effect on the potential of LVDC: If DC were used in buildings, solely or together with AC, how would that change the competitiveness of LVDC?
• Self-sufficient (partially or completely) communities and microgrids: What are the pos-sible mutual impacts of microgrids and LVDC, considering especially those parts of the rural networks that are challenging, for instance long lateral aerial lines with only a few customers, network parts having customers with only occasional consumption, and tar-gets vulnerable to environmental conditions?
105
References
ABB (2017). MEDIUM VOLTAGE PRODUCTS, Technical Application Papers No. 24, Medium voltage direct current applications. [Online]. Available:
https://library.e.abb.com/public/8fda3b49efca49b6b525cabe96c8ae85/AP Corrente continua in media tensione(EN)- 1VCP000681.pdf.
Antoniou, D., Tzimas, A., and Rowland, S. M. (2015). “Transition from alternating current to direct current low voltage distribution networks.”IET Gener. Transm. Distrib. vol. 9, no. 12, pp. 1391–1401.
Barkin, O. et al. (2014).Power Industry in Russia — Challenges of Development Model Selec-tion. National Reseach University, Higher School of Economics, HSE Publishing House, Moscow.
Blimpo, M. P. and Cosgrove-Davies, M. (2019).Electricity Access in Sub-Saharan Africa: Up-take, Reliability, and Complementary Factors for Economic Impact.Africa Development Forum series. Washington, DC: World Bank.
Bolshakov, A. (2016).Investigation of the applicability of LVDC microgrids in utility distri-bution in Russia. Master’s Thesis. Lappeenranta University of Technology, Lappeenranta, Finland.
Casady, J. and Palmour, J. (2014). Power products commercial roadmap for SiC from 2012-2020, Power products rel data & pricing forecasts for 650V-15kV SiC power modules, MOSFETs & diodes. CREE Inc. [Online]. Available: https://www.nist.gov/document-2374.
CEER (2018).Incentives Schemes for Regulating Distribution System Operators, including for innovation, A CEER Conclusions Paper. Ref: C17-DS-37-05.
Cho, Y. et al. (2017). “Construction of actual LVDC distribution line.”CIRED - Open Access Proceedings Journalvol. 2017, no. 1, pp. 2179–2182.
Chung, H.S, Wang, H., Blaabjerg, F., and Pecht, M. (2016).Reliability of Power Electronic Converter Systems. The Institution of Engineering and Technology, London.
Demidov, I. et al. (2019). “Techno-Economic Analysis of Network Configuration of PV-Based Off-Grid Distribution System.” In25th International Conference and Exhibition of Elec-tricity Distribution (CIRED 2019). 3–6 Jun. 2019, Madrid, Spain.
Demidov, I. (2018).Fusion grid concept design and techno-economic analysis for developing countries. Master’s Thesis. Lappeenranta University of Technology, Lappeenranta, Fin-land.
Department of Defence, Systems Management College (2001). SYSTEMS ENGINEERING FUNDAMENTALS. Defence acquisition university press, Fort Belvoir, Virginia 22060-5565.
Directive (EU) 2019/944. Directive (EU) 2019/944 of the European Parliament and of the Council of 5 June 2019 on common rules for the internal market for electricity and amend-ing Directive 2012/27/EU (Text with EEA relevance.) [Online]. Available: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32019L0944.
105
References
ABB (2017). MEDIUM VOLTAGE PRODUCTS, Technical Application Papers No. 24, Medium voltage direct current applications. [Online]. Available:
https://library.e.abb.com/public/8fda3b49efca49b6b525cabe96c8ae85/AP Corrente continua in media tensione(EN)- 1VCP000681.pdf.
Antoniou, D., Tzimas, A., and Rowland, S. M. (2015). “Transition from alternating current to direct current low voltage distribution networks.”IET Gener. Transm. Distrib. vol. 9, no. 12, pp. 1391–1401.
Barkin, O. et al. (2014).Power Industry in Russia — Challenges of Development Model Selec-tion. National Reseach University, Higher School of Economics, HSE Publishing House, Moscow.
Blimpo, M. P. and Cosgrove-Davies, M. (2019).Electricity Access in Sub-Saharan Africa: Up-take, Reliability, and Complementary Factors for Economic Impact.Africa Development Forum series. Washington, DC: World Bank.
Bolshakov, A. (2016).Investigation of the applicability of LVDC microgrids in utility distri-bution in Russia. Master’s Thesis. Lappeenranta University of Technology, Lappeenranta, Finland.
Casady, J. and Palmour, J. (2014).Power products commercial roadmap for SiC from 2012-2020, Power products rel data & pricing forecasts for 650V-15kV SiC power modules, MOSFETs & diodes. CREE Inc. [Online]. Available: https://www.nist.gov/document-2374.
CEER (2018).Incentives Schemes for Regulating Distribution System Operators, including for innovation, A CEER Conclusions Paper. Ref: C17-DS-37-05.
Cho, Y. et al. (2017). “Construction of actual LVDC distribution line.”CIRED - Open Access Proceedings Journalvol. 2017, no. 1, pp. 2179–2182.
Chung, H.S, Wang, H., Blaabjerg, F., and Pecht, M. (2016).Reliability of Power Electronic Converter Systems. The Institution of Engineering and Technology, London.
Demidov, I. et al. (2019). “Techno-Economic Analysis of Network Configuration of PV-Based Off-Grid Distribution System.” In25th International Conference and Exhibition of Elec-tricity Distribution (CIRED 2019). 3–6 Jun. 2019, Madrid, Spain.
Demidov, I. (2018).Fusion grid concept design and techno-economic analysis for developing countries. Master’s Thesis. Lappeenranta University of Technology, Lappeenranta, Fin-land.
Department of Defence, Systems Management College (2001). SYSTEMS ENGINEERING FUNDAMENTALS. Defence acquisition university press, Fort Belvoir, Virginia 22060-5565.
Directive (EU) 2019/944. Directive (EU) 2019/944 of the European Parliament and of the Council of 5 June 2019 on common rules for the internal market for electricity and amend-ing Directive 2012/27/EU (Text with EEA relevance.) [Online]. Available: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32019L0944.
106 References
Doolla, S., Singh, A., and Banerjee, R. (2016).Demand Response in India. Technology Assess-ment, M&V Approach, and Framework for DR Implementation. Shakti Sustainable Energy Foundation and Indian Institute of Technology Bombay.
Dragicevic, T., Vasquez, J. C., Guerrero, J. M., and Skrlec, D. (2014). “Advanced LVDC Elec-trical Power Architectures and Microgrids: A step toward a new generation of power dis-tribution networks.”IEEE Electrific. Mag.vol. 2, no. 1, pp. 54–65.
Dragiˇcevi´c, T., Guerrero, J. M., and Vasquez, J. C. (2014). “A Distributed Control Strategy for Coordination of an Autonomous LVDC Microgrid Based on Power-Line Signaling.”IEEE Trans. Ind. Electron.vol. 61, no. 7, pp. 3313–3326.
Dragiˇcevi´c, T., Lu, X., Vasquez, J. C., and Guerrero, J. M. (2016). “DC Microgrids—Part II:
A Review of Power Architectures, Applications, and Standardization Issues.”IEEE Trans.
Power Electron.vol. 31, no. 5, pp. 3528–3549.
D´ıaz, E. R. et al. (2015). “Intelligent DC Microgrid living Laboratories - A Chinese-Danish cooperation project.” InIEEE First International Conference on DC Microgrids (ICDCM 2015), pp. 365–370.
Eden, R. and Liao, J. (2016). MARKET FORECASTS FOR SILICON CARBIDE & GAL-LIUM NITRIDE POWER SEMICONDUCTORS. [Online]. Available: http://www.apec-conf.org/Portals/0/Industry Session Presentations/2016/SiC GaNForecast.pdf.
EIA/IS-632 (2015).Systems Engineering. SAE international.
Ellert, C. et al. (June 2017). “Modular ICT based Energy Management System for a LVDC-microgrid with local PV production and integrated electrochemical storage.” InIEEE Sec-ond International Conference on DC Microgrids (ICDCM 2017), pp. 274–278.
Emhemed, A. A. S. and Burt, G. M. (2014). “An Advanced Protection Scheme for Enabling an LVDC Last Mile Distribution Network.”IEEE Trans. Smart Gridvol. 5, no. 5, pp. 2602–
2609.
Energiavirasto (2015). S¨ahk¨onjakeluverkon verkkokomponenttien yksikk¨ohinnat 2016–2023.
[Unit price list of network components for 2016–2023] (in Finnish). [Online]. Avail-able: https://energiavirasto.fi/documents/11120570/12766832/Verkkokomponentit-ja-yksikk¨ohinnat-2016-2023.xlsx/7bd40be6-7486-fa81-fbef-3363c71d008e.
Ensto (2018). LVDC: Toimintavarma ja luotettava s¨ahk¨overkko. [Online]. Available:
https://www.ensto.com/fi/yhtio/uutiset-ja-media/artikkelit/lvdc-toimintavarma-ja-luotettava-sahkoverkko/.
Eurelectric (2013). POWER DISTRIBUTION IN EUROPE FACTS & FIGURES.
Union of the Electricity Industry - EURELECTRIC. [Online]. Available:
https://www3.eurelectric.org/media/113155/dso report-web final-2013-030-0764-01-e.pdf.
European Commission (2013).DG ENER Working Paper, The future role and challenges of Energy Storage. [Online]. Available: https://ec.europa.eu/energy/sites/ener/files/energy -storage.pdf.
European Commission (2016).EU Reference Scenario 2016 Energy, transport and GHG emis-sions - Trends to 2050.
106 References
Doolla, S., Singh, A., and Banerjee, R. (2016).Demand Response in India. Technology Assess-ment, M&V Approach, and Framework for DR Implementation. Shakti Sustainable Energy Foundation and Indian Institute of Technology Bombay.
Dragicevic, T., Vasquez, J. C., Guerrero, J. M., and Skrlec, D. (2014). “Advanced LVDC Elec-trical Power Architectures and Microgrids: A step toward a new generation of power dis-tribution networks.”IEEE Electrific. Mag.vol. 2, no. 1, pp. 54–65.
Dragiˇcevi´c, T., Guerrero, J. M., and Vasquez, J. C. (2014). “A Distributed Control Strategy for Coordination of an Autonomous LVDC Microgrid Based on Power-Line Signaling.”IEEE Trans. Ind. Electron.vol. 61, no. 7, pp. 3313–3326.
Dragiˇcevi´c, T., Lu, X., Vasquez, J. C., and Guerrero, J. M. (2016). “DC Microgrids—Part II:
A Review of Power Architectures, Applications, and Standardization Issues.”IEEE Trans.
Power Electron.vol. 31, no. 5, pp. 3528–3549.
D´ıaz, E. R. et al. (2015). “Intelligent DC Microgrid living Laboratories - A Chinese-Danish cooperation project.” InIEEE First International Conference on DC Microgrids (ICDCM 2015), pp. 365–370.
Eden, R. and Liao, J. (2016). MARKET FORECASTS FOR SILICON CARBIDE & GAL-LIUM NITRIDE POWER SEMICONDUCTORS. [Online]. Available: http://www.apec-conf.org/Portals/0/Industry Session Presentations/2016/SiC GaNForecast.pdf.
EIA/IS-632 (2015).Systems Engineering. SAE international.
Ellert, C. et al. (June 2017). “Modular ICT based Energy Management System for a LVDC-microgrid with local PV production and integrated electrochemical storage.” InIEEE Sec-ond International Conference on DC Microgrids (ICDCM 2017), pp. 274–278.
Emhemed, A. A. S. and Burt, G. M. (2014). “An Advanced Protection Scheme for Enabling an LVDC Last Mile Distribution Network.”IEEE Trans. Smart Gridvol. 5, no. 5, pp. 2602–
2609.
Energiavirasto (2015). S¨ahk¨onjakeluverkon verkkokomponenttien yksikk¨ohinnat 2016–2023.
[Unit price list of network components for 2016–2023] (in Finnish). [Online]. Avail-able: https://energiavirasto.fi/documents/11120570/12766832/Verkkokomponentit-ja-yksikk¨ohinnat-2016-2023.xlsx/7bd40be6-7486-fa81-fbef-3363c71d008e.
Ensto (2018). LVDC: Toimintavarma ja luotettava s¨ahk¨overkko. [Online]. Available:
https://www.ensto.com/fi/yhtio/uutiset-ja-media/artikkelit/lvdc-toimintavarma-ja-luotettava-sahkoverkko/.
Eurelectric (2013). POWER DISTRIBUTION IN EUROPE FACTS & FIGURES.
Union of the Electricity Industry - EURELECTRIC. [Online]. Available:
https://www3.eurelectric.org/media/113155/dso report-web final-2013-030-0764-01-e.pdf.
European Commission (2013).DG ENER Working Paper, The future role and challenges of Energy Storage. [Online]. Available: https://ec.europa.eu/energy/sites/ener/files/energy -storage.pdf.
European Commission (2016).EU Reference Scenario 2016 Energy, transport and GHG emis-sions - Trends to 2050.
References 107
European Commission (2019).HORIZON 2020 WORK PROGRAMME 2018-2020 19. General Annexes.
Eurostat (2019). Energy prices in 2018, Household energy prices in the EU increased compared with 2017. [Online]. Available:
https://ec.europa.eu/eurostat/documents/2995521/9802432/8-21052019-AP-EN.pdf/7f42181d-d795-4ce1-9dde-ba93fe247166.
Forsberg, K. and Mooz, H. (1994). “The Relationship of System Engineering to the Project Cycle.” InNational Council On Systems Engineering (NCOSE) and American Society for Engineering Management (ASEM). 21–23 Oct. 1991, Chattanooga, USA.
Gavrikova, E. et al. (2019). “Clean Energy Sources: Insights from Russia.”Resourcesvol. 8, no. 2.
Glasgo, B., Azevedo, I. L., and Hendrickson, C. (2016). “How much electricity can we save by using direct current circuits in homes? Understanding the potential for electricity savings and assessing feasibility of a transition towards DC powered buildings.”Applied Energy vol. 180, pp. 66 –75.
Graessler, I., Hentze, J., and Bruckmann, T. (2018). “V-MODELS FOR INTERDISCI-PLINARY SYSTEMS ENGINEERING.” InINTERNATIONAL DESIGN CONFERENCE - DESIGN 2018.
Haakana, J. (2013).Impact of reliability of supply on long-term development approaches to elec-tricity distribution networks. Doctoral dissertation, Acta Universitatis Lappeenrantaensis 547, Lappeenranta University of Technology, Lappeenranta, Finland, 85 p.
Hayn, M., Bertsch, V., and Fichtner, W. (2014). “Electricity load profiles in Europe: The im-portance of household segmentation.”Energy Research & Social Sciencevol. 3, pp. 30
Hayn, M., Bertsch, V., and Fichtner, W. (2014). “Electricity load profiles in Europe: The im-portance of household segmentation.”Energy Research & Social Sciencevol. 3, pp. 30