标题：Improved autonomous converter control for multi-terminal HVDC networks considering line impedance effect in long-distance interconnections

作者：Wanning Zheng ; Jiabing Hu ; Meiqing Zhang ; Miao Miao

摘要：Multi-terminal high voltage direct current (HVDC) networks with long-distance interconnections across the region has extensive demands all over the world, particularly for integrating large-scale renewable generations in China. Autonomous converter control based on voltage-droop strategy, widely accepted in DC Microgrid, is however flawed in multi-terminal HVDC networks with long-distance interconnections. That is because DC line impedance makes converters not be able to accurately reach the active power reference value given by the secondary control. This paper proposes an improved autonomous converter control method to reduce the steady-state error of active power in multiterminal HVDC networks. It first illustrates the real operating condition of each converter with traditional autonomous converter control in a multi-terminal HVDC network, and further investigates the relationship between the error of DC current and the steady-error of active power. Then the effects of DC line impedance and the slope of voltage-droop control on the steady-state error of active power flow is analyzed. Based on the analysis, an improved autonomous converter control method is presented to ensure each converter accurately tracking the reference of DC current point calculated from the active power reference and ideal DC voltage. Comparisons between the traditional and presented methods are studied, and eventually simulation tests in PSCAD verify the availability of the proposed methed.

发表于：12th IET International Conference on AC and DC Power Transmission (ACDC 2016)