Solid State Circuit Breakers In Dc Distribution Networks

Author : Yue Zhang (Electrical engineer)
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (135 download)

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Download or read book T-type Modular DC Circuit Breaker (T-breaker) with Integrated Energy Storage for Future DC Networks written by Yue Zhang (Electrical engineer) and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct current power distribution and dc microgrids have been gaining momentum in recent years for various applications. However, compared to traditional ac systems, dc systems still need to address technical challenges such as fault current management/protection, power flow control, power quality management, and potential system instability. This dissertation proposes the T-Breaker system seeking to address these issues in an all-in-one device with modular multilevel converter functions. It is characterized by its use of locally integrated energy storage, high scalability, and high tolerance to control signal mismatch during the fast network transients. This is a paradigm shift from traditional solid-state circuit breakers as the proposed T-Breaker not only protects against faults, but can also function as an energy router with unparalleled ancillary functions for dc grids. This dissertation starts with a systematic overview of the remaining challenges of dc distribution covering the existing dc circuit breaker technologies, particularly on solid-state circuit breakers, as well as the needs and current status of compensation in dc networks. Taking inspiration from the series and shunt compensation devices in ac transmission and distribution systems, the T-Breaker system with half-bridge sub-modules is derived from traditional solid-state circuit breakers. The proposed circuit has modular multilevel converter functions with an increased number of active switches but no conduction loss penalty when compared with traditional solutions. The basic operation modes and the circuit analysis are carried out, and the limitations are identified for the half-bridge T-Breaker. In order to improve upon these drawbacks, the full-bridge T-Breaker is proposed, with improved performance in sub-module voltage injection to the line, and lowering of total heat flux for more compact thermal designs. Along with the basic functionalities of both T-Breaker topologies, the series and shunt compensation functions are also introduced and demonstrated with simulation results. Extended discussions are carried out for the two active current limiting methods in T-Breaker: modulated voltage injection and driving the semiconductor devices into current clamping regions. The discussion includes equivalent circuit models, circuit simulations, and test results. A review of existing solutions and literature of fault current limiters are also provided. Two prototypes were developed at 1 kV, 500 A and 20 kV, 250 A in order to demonstrate the functionalities of the T-Breaker for different applications and voltage levels. Targeting the high-current aircraft and commercial building applications, the 1-kV, 500-A, half-bridge T-Breaker system is demonstrated with 99.58% conduction efficiency at full load and up to 5 kA of current breaking capability. Targeting electric ships and utility scale dc microgrids, the full-bridge T-Breaker is demonstrated at 20 kV and up to 250 A of conduction current. The detailed component sizing and design procedures are discussed. The key design challenges, including paralleling power modules for 500-A operation, assembly-level insulation design with 3D printed mechanical housings for medium voltage, and high current, medium voltage printed circuit board bus bar designs with specialized solder masks and terminal arrangement, are also presented.