海上风电直流汇集DC/DC系统实时仿真方法

Real-time simulation method for a DC/DC collection system in an offshore wind farm

随着深远海风电的开发与快速发展,采用柔性直流输电技术逐渐成为海上风电系统的首选方案。然而,海上风电及其输电系统的安全运行仍面临严峻的挑战。实时仿真技术能低成本、快速模拟各种复杂运行工况,得到越来越多的关注。直流汇集DC/DC系统是海上风电系统中的关键设备,其复杂的级联结构、数量众多的元件和更高的开关频率都给实时仿真带来了巨大的挑战。为此,提出一种海上风电直流汇集DC/DC系统实时仿真方法,通过仿真算法的并行设计和等效模型的构建两个步骤,实现大规模海上风电直流汇集DC/DC系统的小步长实时仿真。首先,将EMTP算法重新设计为适用于实时仿真的并行算法,并基于此构建直流汇集DC/DC系统子模块的等效模型。其次,根据子模块之间的串联耦合关系,构建直流汇集DC/DC系统的多端口等效模型。最后,在CPU-FPGA异构实时仿真平台中进行海上风电直流汇集DC/DC系统在多种工况下的实时仿真,并与PSCAD/EMTDC离线仿真结果进行对比,验证了所提实时仿真方法的准确性和高效性。

With the rapid development of offshore wind power,flexible DC transmission technology has gradually become the preferred solution for offshore wind power systems.However,their safe operation still faces challenges.Real-time simulation technology has attracted more and more attention.It can simulate various complex operating conditions in a low cost and fast way.The DC/DC collection system is the key device in offshore wind farms,and its complicated cascade structures,the large number of components and the higher switching frequencies bring great challenges to the real-time simulation.In this paper,a real-time simulation method for a DC/DC collection system in an offshore wind farm is proposed,one which realizes the small-step real-time simulation of large-scale DC/DC collection systems in two steps:parallel design of the simulation algorithm and equivalent modeling of the system.First,the EMTP algorithm is redesigned as a parallel simulation algorithm for real-time simulation.The equivalent model of the submodule of DC/DC collection system is built based on a parallel real-time simulation algorithm.Second,the multi-port equivalent model of the DC/DC collection system is built based on the series coupling relationship of the submodule.Finally,the real-time simulation of the DC/DC collection system in various operating conditions is carried out on the CPU-FPGA heterogeneous real-time simulation platform.The results are compared with offline simulation in PSCAD/EMTDC to verify the accuracy and efficiency of the proposed real-time simulation method.