藏东南光伏基地全直流汇集送出方案及其控制策略研究

Research on the full DC collection and transmission scheme for the photovoltaic base in Southeast Tibet and its control strategy

藏东南地区光伏资源丰富,其大规模开发利用契合我国“双碳”目标,亟需确定合适的汇集与送出方式。受限于西藏地区自然环境与电网建设条件,具备输送距离远、同电压等级下输送容量大、不存在无功电压支撑问题等优点的全直流汇集与送出方案较传统交流方案更具优势。首先,基于藏东南光伏基地汇集送出场景,提出全直流汇集送出推荐组网方案。然后,针对直流变压器和泄能装置等关键设备的拓扑结构、系统接地方案、系统控制保护策略进行探讨。最后,在PSCAD/EMTDC中搭建10000 MW光伏全直流汇集送出系统仿真模型,验证了所提藏东南光伏基地全直流系统方案的可行性。

Southeast Tibet is rich in photovoltaic energy,and its large-scale utilization is in line with China's carbon peaking and carbon neutrality goals.Thus,it is urgent to choose an appropriate collection and transmission method.Limited by the natural environment and power grid construction conditions in southeast Tibet,the full DC collection and transmission scheme with the advantages of long transmission distance,no reactive power problems,and high efficiency is superior to the traditional AC scheme.Firstly,a recommended networking mode for a full DC collection and transmission scheme is proposed in view of the collection and transmission scenarios of a photovoltaic base in southeast Tibet.Secondly,the topology of the key equipment,such as DC transformers and energy dissipation devices,the system grounding scheme and its control and protection strategies are discussed.Finally,a simulation model of a 10,000 MW photovoltaic full DC collection and transmission system is built in PSCAD/EMTDC,and the feasibility of the proposed scheme for the photovoltaic in southeast Tibet is verified.