A New Method to Obtain the Droop Control Coefficient in a Meshed DC System Based on Automatically Decentralized Control
Cao Xin1, Han Minxiao1, Zhou Guangyang1, Zhang Lidong2
1. School Electrical and Electronic Engineering North China Electric Power University Beijing 102206 China; 2. ABB Corporate Research Vasteras 72178 Sweden
Abstract Recent researches focus on droop control coefficient calculation in the radial DC system, and fewer researches investigate its calculation in complex DC systems. This paper proposed a new method for droop control coefficient calculation in a meshed DC system based on automatically decentralized control. Firstly, the information of the converter was collected and interchanged by the system control layer of the automatically decentralized control. After that, all the converters obtained the same global information by the optimal power flow model to calculate the reference values of DC voltage and active power. Then, the virtual node was defined and its voltage was equal to the average of the reference DC voltage. The nodes where the voltage is equal to the virtual voltage were selected, and the system was simplified into radial topology. Subsequently, the reference resistances between nodes and the virtual node under the optimal condition could be obtained, the real resistances between nodes and the virtual node under current condition also could be calculated. Herein, the droop control coefficients are equal to the inverse of difference between the virtual and real resistances. Finally, a 6-terminal MMC-MTDC model was established in PSCAD/EMTDC, and the simulations verified the proposed method.
Cao Xin,Han Minxiao,Zhou Guangyang等. A New Method to Obtain the Droop Control Coefficient in a Meshed DC System Based on Automatically Decentralized Control[J]. Transactions of China Electrotechnical Society, 2020, 35(24): 5164-5174.
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2020, Vol. 35 
