New Series Type Hybrid Circuit Breakers: Fault Protection with Ultralow Loss and Ultrafast Response for Future DC Power Networks

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Electricity, in its predominant form of alternating current (AC), is at the heart of modern civilization. However, direct current (DC) electricity is re-emerging, long after losing the War of Currents over a century ago. DC inherently offers higher efficiency, better stability, better match with modern electrical loads, and easier integration of renewable and storage resources than AC. With voltage conversion easily facilitated by modern power electronics, DC power is gaining tractions in applications such as high-voltage direct current (HVDC) transmission, DC data centers, photovoltaic farms, electric vehicle (EV) charging infrastructures, shipboard and aircraft power systems. However, one major technical barrier to the DC paradigm shift is the lack of effective DC circuit protection technology. While intensive research has been addressing this important need, so far none of the existing solutions can meet the power loss, response time, and cost requirements of the future DC grids all at the same time. Nonconventional game-changing DC fault protection concepts need to be further explored. The objective of this NSERC Discovery program is to develop a fundamentally new series-type hybrid circuit breaker (S-HCB) architecture that provides DC fault protection with ultralow power loss (<10W), ultrafast response (<10µs), and low cost. The proposed S-HCB concept is distinct from prior art solid state circuit breaker (SSCB) or conventional parallel-type HCB in terms of operation principle and physical design. It raises an array of unique scientific/engineering challenges of multi-scale and multi-physics nature, ranging from basic electromagnetics science to power electronics topology/control to high-voltage engineering to power system engineering. The program is structured around four main thrusts: 1) modeling and simulation of the S-HCB concept using multi-physics simulation tools; 2) prototyping and experimental demonstration of the S-HCB concept at a power level of 2kV/50A and 10kV/100A, respectively; 3) feasibility study of extending the S-HCB concept to the HVDC domain (e.g., 500kV/1kA) and publication of guidelines and recommendations; and 4) collaboration with industry to identify commercialization opportunity for the research outcome. If successfully developed, the S-HCB architecture will help usher in an era of greener DC power with significant reduction in carbon emission. It will generate scientific knowledge, intellectual property, and design tools that advance the field of electrical engineering. Furthermore, it will provide an excellent platform for training undergraduate and graduate students, and PDFs, who are in high demand in academia and industry. Lastly, it will include a pilot study of a "DC Village Nanogrid" concept for the 200,000 Canadians (including the First Nations people) who live in the remote off-grid communities to integrate renewable energy and energy storage, and to reduce their dependency on fossil fuels.