CAJ | 학술논문

该文提出了一种多端口直流–直流自耦变压器的拓扑，该多端口直流自耦变压器用于互联多个直流电压等级不同的直流系统。提出了多端口直流自耦变压器的潮流直接分析法以及潮流分解分析法，推导了多端口直流自耦变压器中各换流器额定电压与额定功率设计方法，设计了多端口直流自耦变压器的控制策略。以一个三端口直流自耦变压器为测试算例，在PSCAD/EMTDC下仿真验证了多端口直流自耦变压器的技术可行性。以互联±250、±320 kV和±400 kV直流系统为例，假设±250 kV 和±320 kV 系统的额定输入/输出功率分别为500 MW和1000 MW，采用常规的多端口直流–直流变换器技术所需要的换流器总容量为3000 MW，而采用多端口直流自耦变压器技术所需要总的换流器仅为775 MW，所使用的换流器总容量仅为现有技术的26%，显著节省了成本，降低了运行损耗。
해문제출료일충다단구직류–직류자우변압기적탁복，해다단구직류자우변압기용우호련다개직류전압등급불동적직류계통。제출료다단구직류자우변압기적조류직접분석법이급조류분해분석법，추도료다단구직류자우변압기중각환류기액정전압여액정공솔설계방법，설계료다단구직류자우변압기적공제책략。이일개삼단구직류자우변압기위측시산례，재PSCAD/EMTDC하방진험증료다단구직류자우변압기적기술가행성。이호련±250、±320 kV화±400 kV직류계통위례，가설±250 kV 화±320 kV 계통적액정수입/수출공솔분별위500 MW화1000 MW，채용상규적다단구직류–직류변환기기술소수요적환류기총용량위3000 MW，이채용다단구직류자우변압기기술소수요총적환류기부위775 MW，소사용적환류기총용량부위현유기술적26%，현저절성료성본，강저료운행손모。
This paper proposed a multiport DC-DC autotransformer to interconnect multiple DC grids with different DC voltages. Decomposed power flow analysis and direct power flow analysis for the multiport DC auto were proposed. Methods of dimensioning the voltage and power rating of each of the VSC converters in the multiport DC auto were derived. Controllers were designed to keep stable operation of the multiport DC auto. Simulation results of a 3-port DC auto demonstrated the technical feasibility of the multiport DC-DC autotransformer. Taking a 3-port DC auto interconnecting ±250, ±320 and ±400 kV DC grids as an example, suppose the power rating for each of the port is 500, 1 000 and 1 500 MW respectively, the 3-port DC auto only needs 775 MW VSC converters while a total of 3 000 MW VSC converters is required for conventional technology. The multiport DC auto can save significant amount of investment compared with conventional DC-DC technology.