Events

EXCOM Meeting for IEEE PES Seattle Officers Virtual: https://events.vtools.ieee.org/m/521446

Synopsis: Please feel free to check out the work and thoughts of Prof. Ethem Alpaydın, Ph.D., https://mitpress.mit.edu/author/ethem-alpaydn-10375/ on Google Scholar at https://scholar.google.com/citations?user=lXYKgiYAAAAJ&hl=tr and generally on the Internet. Then, please feel free to submit your questions to Prof. Ethem Alpaydın - via Twitter by using the hashtag #ProfAlpaydinAMA and tagging @vishnupendyala - emailing vspendyala(at)hotmail(dot)com with #ProfAlpaydinAMA in the subject Selected questions will be answered by Prof. Alpaydin during the session. The audience may be able to ask follow-up questions during the session, using the Chat feature. --------------------------------------------------------------- By registering for this event, you agree that IEEE and the organizers are not liable to you for any loss, damage, injury, or any incidental, indirect, special, consequential, or economic loss or damage (including loss of opportunity, exemplary or punitive damages). The event will be recorded and will be made available for public viewing. Co-sponsored by: Vishnu S. Pendyala, SJSU Speaker(s): Dr. Vishnu S. Pendyala, Prof. Alpaydın Virtual: https://events.vtools.ieee.org/m/537179

High Voltage DC Transmission has seen rapid technology advances in the last 20 years driven by the implementation of VSC (Voltage Source Converters) at GW powers and in particular introduction of MMC (Modular Multilevel Converters). The development of interconnected DC transmission grids requires significant further advance from the existing point-to-point HVDC links. It is widely believed that complex DC power grids can be built with comparable performance, reliability, flexibility and losses as traditional AC grids. The primary motivation for DC grid development is the need for power flow and trading between many DC terminals, as an example in the proposed (350 GW) North Sea DC grid, or EU-wide overlay DC grid. AC transmission is not feasible with long subsea cables, and it is inferior to DC systems in many other conditions. This presentation addresses the options and challenges with DC grid development, referring also to state-of-art technology status. Zhangbei 4-terminal DC system (China, 2020) represents the first implemented GW-scale meshed DC transmission grid, which employs bipolar ring topology with overhead lines and 16 DC Circuit Breakers. However, multiple studies illustrate advantages of some radial, hub-based or segmented topologies, because of component costs, and challenges with interoperability, ownership, DC markets, operation, security and reliability. MMC concepts, including half-bridge and full-bridge modules, will underpin DC grid converters and further advances like hybrid LCC/MMC converters have been implemented recently. DC/DC converters at hundreds of MW are not yet commercially available but there is lot of research world-wide, and some lower-power prototypes have been demonstrated. DC/DC converters may take multiple functions including: DC voltage stepping (transformer role), DC fault interruption (DC CB role) and power flow control. Multiport DC hubs can be viewed as electronic DC substations, capable of interconnecting multiple DC lines. Very fast DC CB circuit breakers (2 ms) have become commercially available recently, but the cost is considerably higher than AC CBs. Slightly slower mechanical DC CBs (5-8 ms) are also available from multiple vendors, while new technical solutions are emerging worldwide for achieving faster operation with lower size/weight/costs. DC grid modelling will face the new challenge of numerous converters dynamically coupled through low-impedance DC cables/lines. A compromise between simulation speed and accuracy is required, leading to some average-value modelling, commonly in rotating DQ frame, but capturing very fast dynamics and variable structure to represent fault conditions. The principles of control of DC grids have been developed. DC systems have no system-wide common frequency to indicate power unbalance, and voltage responds to local and global loading rather than reactive power flow. DC grid dynamics are 2 orders of magnitude faster than traditional AC systems and most components will be controllable implying numerous, fast control loop interactions. Because of lack of inertia, and minimal overload capability for semiconductors, DC grid primary and secondary control should be feedback-based (man-made), fast, and distributed. International standardization efforts have begun. The protection of DC grids is a significant technical challenge, both in terms of components and protection logic. The selectivity has been demonstrated within 0.5 ms timeframe using commercial and open-source DC relays. Nevertheless, grid operators have expressed concerns with self-protection on various components, back-up grid-wide protection, interoperability, and in general if we can achieve power transfer security levels comparable with AC grids and acceptable to stakeholders. Speaker(s): Dragan Jovcic, Agenda: • 5:30 – 5:45 PM: Welcome & Introduction • 5:45 – 6:45 PM: Distinguished Lecturer Technical Talk • 6:45 – 7:15 PM: Q&A Session • 7:15 – 7:30 PM: Closing Remarks & Acknowledgements 1825 Schweitzer Drive, Pullman, Washington, United States, 99163

High Voltage DC Transmission has seen rapid technology advances in the last 20 years driven by the implementation of VSC (Voltage Source Converters) at GW powers and in particular introduction of MMC (Modular Multilevel Converters). The development of interconnected DC transmission grids requires significant further advance from the existing point-to-point HVDC links. It is widely believed that complex DC power grids can be built with comparable performance, reliability, flexibility and losses as traditional AC grids. The primary motivation for DC grid development is the need for power flow and trading between many DC terminals, as an example in the proposed (350 GW) North Sea DC grid, or EU-wide overlay DC grid. AC transmission is not feasible with long subsea cables, and it is inferior to DC systems in many other conditions. This presentation addresses the options and challenges with DC grid development, referring also to state-of-art technology status. Zhangbei 4-terminal DC system (China, 2020) represents the first implemented GW-scale meshed DC transmission grid, which employs bipolar ring topology with overhead lines and 16 DC Circuit Breakers. However, multiple studies illustrate advantages of some radial, hub-based or segmented topologies, because of component costs, and challenges with interoperability, ownership, DC markets, operation, security and reliability. MMC concepts, including half-bridge and full-bridge modules, will underpin DC grid converters and further advances like hybrid LCC/MMC converters have been implemented recently. DC/DC converters at hundreds of MW are not yet commercially available but there is lot of research world-wide, and some lower-power prototypes have been demonstrated. DC/DC converters may take multiple functions including: DC voltage stepping (transformer role), DC fault interruption (DC CB role) and power flow control. Multiport DC hubs can be viewed as electronic DC substations, capable of interconnecting multiple DC lines. Very fast DC CB circuit breakers (2 ms) have become commercially available recently, but the cost is considerably higher than AC CBs. Slightly slower mechanical DC CBs (5-8 ms) are also available from multiple vendors, while new technical solutions are emerging worldwide for achieving faster operation with lower size/weight/costs. DC grid modelling will face the new challenge of numerous converters dynamically coupled through low-impedance DC cables/lines. A compromise between simulation speed and accuracy is required, leading to some average-value modelling, commonly in rotating DQ frame, but capturing very fast dynamics and variable structure to represent fault conditions. The principles of control of DC grids have been developed. DC systems have no system-wide common frequency to indicate power unbalance, and voltage responds to local and global loading rather than reactive power flow. DC grid dynamics are 2 orders of magnitude faster than traditional AC systems and most components will be controllable implying numerous, fast control loop interactions. Because of lack of inertia, and minimal overload capability for semiconductors, DC grid primary and secondary control should be feedback-based (man-made), fast, and distributed. International standardization efforts have begun. The protection of DC grids is a significant technical challenge, both in terms of components and protection logic. The selectivity has been demonstrated within 0.5 ms timeframe using commercial and open-source DC relays. Nevertheless, grid operators have expressed concerns with self-protection on various components, back-up grid-wide protection, interoperability, and in general if we can achieve power transfer security levels comparable with AC grids and acceptable to stakeholders. Speaker(s): , Dragan Jovcic Agenda: • 5:00 – 5:15 PM: Welcome & Introduction • 5:15 – 6:15 PM: Distinguished Lecturer Technical Talk • 6:15 – 6:45 PM: Q&A Session • 6:45 – 7:00 PM: Closing Remarks & Acknowledgements Room: 303, Bldg: Electrical and Computer Engineering, 185 W Stevens Wy NE, Seattle, Washington, United States