新能源基地多端柔性直流汇集系统运行灵活性研究

Operational Flexibility Optimization of Renewables Generation Multi-terminal Flexible DC Collector System

基于模块化多电平换流器(modularmulti-level converter,MMC)的多端柔性直流(multi-terminal high voltage direct current transmission,MTDC)汇集系统因其灵活的调控能力可提升新能源的消纳水平以及新能源基地的并网友好性。该文针对新能源基地多端柔性直流汇集系统的运行灵活性开展研究。针对新能源基地出力不确定性和相关性,采用Pair-copula模型结合2m+1点估计法进行建模;考虑风-光-储多源互补和MMC-MTDC协调控制,建立了弃风弃光最小、运行网损最小和直流电压偏差最小的多维度运行灵活性优化模型,利用内点法进行求解;参照张北新能源汇集工程构建算例,验证了所提新能源出力建模方法的有效性;所建的运行灵活性优化模型能够给出多换流站的协调控制策略,同时实现风、光、储等多资源的优化调度;所建模型还可分析汇集系统运行灵活性的影响因素,并能给出汇集系统运行的灵活调节域。

The multi-terminal flexible DC collector system with modular multi-level converters(MMC-MTDC)can greatly improve the consumption level of the new energy sources and the grid-connected friendliness on the new energy bases due to its flexible capabilities of modulation and control.This paper studies deeply into the operational flexibility of renewables generation multi-terminal flexible DC collector system.Aiming at the uncertainty and correlation of the renewable output,the Pair-copula model combining with 2 m+1 point estimate method is initially utilized.Considering wind-light-storage multienergy complementary and MMC-MTDC’s coordination control,the operational flexibility optimization model is built,including multidimensional optimization objective(minimum curtailed renewable energy,minimum power loss,and minimum dc voltage deviation).The model is solved by interior point method.The effectiveness of the proposed new energy sources output modeling method is verified by the simulation model constructed with the reference to the Zhangbei new energy sources collector system.The proposed operational flexibility optimization model can give the coordinated control strategy of the multiple converter stations,achieve the optimal scheduling of multi-sources.Furthermore,the model can be used to analyze the influencing factors of the collector system’s operational flexibility,and to show a flexible regulation domain of the collector system.