1. 国网江苏省电力有限公司电力科学研究院, 江苏省南京市 211103; 2. 东南大学电气工程学院, 江苏省南京市 210096
1. Electric Power Research Institute of State Grid Jiangsu Electric Power Co., Ltd., Nanjing 211103, China; 2. School of Electrical Engineering, Southeast University, Nanjing 210096, China
Focusing on the problems of engineering applications of DC transformer(DCT)in medium-voltage DC distribution network, this paper firstly summarizes the requirements of DCT for practical engineering applications, such as quick recovery form fault, high reliability for power supply and flexible control. An improved submodule topology with isolated half bridge is adopted, and the fault blocking, on-line redundancy, on-load voltage regulation and voltage sharing control of the improved submodule topology are analyzed. Then, several typical engineering problems are discussed, including the power supply mode for submodules, soft start-up strategy and insulation design. Various solutions for these problems are further presented and compared with the adaptability analysis. Furthermore, the energy efficiency improvement which is the key issue for engineering is mainly studied by the analysis of hardware and software. And the corresponding improvement strategies are proposed in several aspects, which include the type selection of materials, design of high frequency transformer, improvement of control strategy and optimization of system energy. Finally, the engineering prospects of miniaturized apparatus are explored. Several schemes for miniaturized apparatus are respectively proposed from the perspectives of specific scenario design, improvement of module topology and application of new materials, and the existing technical bottleneck and corresponding solutions are clarified.
LIU Ruihuang, YANG Jinggang, JIA Yongyong,et al.Engineering Applications of DC Transformer in Medium-voltage DC Distribution Network[J].Automation of Electric Power Systems,2019,43(23):131-140. DOI:10.7500/AEPS20190429020.