BEGIN:VCALENDAR VERSION:2.0 PRODID:IEEE vTools.Events//EN CALSCALE:GREGORIAN BEGIN:VTIMEZONE TZID:America/Los_Angeles BEGIN:DAYLIGHT DTSTART:20260308T030000 TZOFFSETFROM:-0800 TZOFFSETTO:-0700 RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3 TZNAME:PDT END:DAYLIGHT BEGIN:STANDARD DTSTART:20261101T010000 TZOFFSETFROM:-0700 TZOFFSETTO:-0800 RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11 TZNAME:PST END:STANDARD END:VTIMEZONE BEGIN:VEVENT DTSTAMP:20260220T043738Z UID:63776F2F-35DA-48BE-9178-54DA7956A485 DTSTART;TZID=America/Los_Angeles:20260410T170000 DTEND;TZID=America/Los_Angeles:20260410T190000 DESCRIPTION: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 Mu ltilevel Converters). The development of interconnected DC transmission gr ids 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 tra ditional AC grids. The primary motivation for DC grid development is the n eed for power flow and trading between many DC terminals\, as an example i n 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 o ptions and challenges with DC grid development\, referring also to state-o f-art technology status.\n\nZhangbei 4-terminal DC system (China\, 2020) r epresents the first implemented GW-scale meshed DC transmission grid\, whi ch employs bipolar ring topology with overhead lines and 16 DC Circuit Bre akers. However\, multiple studies illustrate advantages of some radial\, h ub-based or segmented topologies\, because of component costs\, and challe nges with interoperability\, ownership\, DC markets\, operation\, security and reliability.\n\nMMC concepts\, including half-bridge and full-bridge modules\, will underpin DC grid converters and further advances like hybri d LCC/MMC converters have been implemented recently. DC/DC converters at h undreds of MW are not yet commercially available but there is lot of resea rch world-wide\, and some lower-power prototypes have been demonstrated. D C/DC converters may take multiple functions including: DC voltage stepping (transformer role)\, DC fault interruption (DC CB role) and power flow co ntrol. Multiport DC hubs can be viewed as electronic DC substations\, capa ble of interconnecting multiple DC lines.\n\nVery fast DC CB circuit break ers (2 ms) have become commercially available recently\, but the cost is c onsiderably 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/weig ht/costs.\n\nDC grid modelling will face the new challenge of numerous con verters dynamically coupled through low-impedance DC cables/lines. A compr omise between simulation speed and accuracy is required\, leading to some average-value modelling\, commonly in rotating DQ frame\, but capturing ve ry fast dynamics and variable structure to represent fault conditions.\n\n 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 capa bility for semiconductors\, DC grid primary and secondary control should b e feedback-based (man-made)\, fast\, and distributed. International standa rdization efforts have begun.\n\nThe protection of DC grids is a significa nt technical challenge\, both in terms of components and protection logic. The selectivity has been demonstrated within 0.5 ms timeframe using comme rcial and open-source DC relays. Nevertheless\, grid operators have expres sed concerns with self-protection on various components\, back-up grid-wid e protection\, interoperability\, and in general if we can achieve power t ransfer security levels comparable with AC grids and acceptable to stakeho lders.\n\nSpeaker(s): \, Dragan Jovcic\n\nAgenda: \n• 5:00 – 5:15 PM: Welcome & Introduction\n• 5:15 – 6:15 PM: Distinguished Lecturer Techn ical Talk\n• 6:15 – 6:45 PM: Q&A Session\n• 6:45 – 7:00 PM: Closin g Remarks & Acknowledgements\n\nRoom: 303\, Bldg: Electrical and Computer Engineering\, 185 W Stevens Wy NE\, Seattle\, Washington\, United States LOCATION:Room: 303\, Bldg: Electrical and Computer Engineering\, 185 W Stev ens Wy NE\, Seattle\, Washington\, United States ORGANIZER:tanya.panomvana@ieee.org SEQUENCE:24 SUMMARY:DC Transmission Grids - Topology\, Components\, Modelling\, Control and Protection Challenges - Prof. Dragan Jovcic URL;VALUE=URI:https://events.vtools.ieee.org/m/540783 X-ALT-DESC:Description: <br /><p class="MsoBodyText">High Voltage DC Transm ission has seen rapid technology advances in the last 20 years driven by t he implementation of VSC (Voltage Source Converters) at GW powers and in p articular introduction of MMC (Modular Multilevel Converters). The develop ment 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\, re liability\, flexibility and losses as traditional AC grids. The primary mo tivation for DC grid development is the need for power flow and trading be tween 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 wit h long subsea cables\, and it is inferior to DC systems in many other cond itions. This presentation addresses the options and challenges with DC gri d development\, referring also to state-of-art technology status.</p>\n<p class="MsoBodyText">Zhangbei 4-terminal DC system (China\, 2020) represent s the first implemented GW-scale meshed DC transmission grid\, which emplo ys bipolar ring topology with overhead lines and 16 DC Circuit Breakers. H owever\, multiple studies illustrate advantages of some radial\, hub-based or segmented topologies\, because of component costs\, and challenges wit h interoperability\, ownership\, DC markets\, operation\, security and rel iability.&nbsp\;&nbsp\;&nbsp\;</p>\n<p class="MsoBodyText">MMC concepts\, including half-bridge and full-bridge modules\, will underpin DC grid conv erters and further advances like hybrid LCC/MMC converters have been imple mented recently. DC/DC converters at hundreds of MW are not yet commercial ly available but there is lot of research world-wide\, and some lower-powe r prototypes have been demonstrated. DC/DC converters may take multiple fu nctions including: DC voltage stepping (transformer role)\, DC fault inter ruption (DC CB role) and power flow control. Multiport DC hubs can be view ed as electronic DC substations\, capable of interconnecting multiple DC l ines.</p>\n<p class="MsoBodyText">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 a vailable from multiple vendors\, while new technical solutions are emergin g worldwide for achieving faster operation with lower size/weight/costs.&n bsp\;</p>\n<p class="MsoBodyText">DC grid modelling will face the new chal lenge of numerous converters dynamically coupled through low-impedance DC cables/lines. A compromise between simulation speed and accuracy is requir ed\, leading to some average-value modelling\, commonly in rotating DQ fra me\, but capturing very fast dynamics and variable structure to represent fault conditions.</p>\n<p class="MsoBodyText">The principles of control of DC grids have been developed. DC systems have no system-wide common frequ ency to indicate power unbalance\, and voltage responds to local and globa l loading rather than reactive power flow. DC grid dynamics are 2 orders o f 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 .</p>\n<p class="MsoBodyText">The protection of DC grids is a significant technical challenge\, both in terms of components and protection logic. Th e selectivity has been demonstrated within 0.5 ms timeframe using commerci al and open-source DC relays. Nevertheless\, grid operators have expressed concerns with self-protection on various components\, back-up grid-wide p rotection\, interoperability\, and in general if we can achieve power tran sfer security levels comparable with AC grids and acceptable to stakeholde rs.</p><br /><br />Agenda: <br /><p>&bull\; 5:00 &ndash\; 5:15 PM: Welcome &amp\; Introduction<br>&bull\; 5:15 &ndash\; 6:15 PM: Distinguished Lectu rer Technical Talk<br>&bull\; 6:15 &ndash\; 6:45 PM: Q&amp\;A Session<br>& bull\; 6:45 &ndash\; 7:00 PM: Closing Remarks &amp\; Acknowledgements</p> END:VEVENT END:VCALENDAR