新能源多馈入直流并网与传统交流并网对比

Contrasting Analysis on Multi-infeed VSC and AC Grid-connection of New Energy

新能源大规模开发,形成区域性的多个能源基地,传统的交流并网容量小、损耗高并且对区域交流系统影响大,柔性直流输电经济稳定且节省输电通道,区域性大型能源基地采用多馈入电压源型直流输电(VSC)并网,然后经电流源型直流输电(LCC)通道外送,能解决上述问题。首先论述了多馈入直流并网的可行性,然后对交直流输电技术进行了对比,并针对其工程应用的性价比进行经济性评估。然后通过设计新能源多馈入直流并网和传统交流并网拓扑结构,并配置两种方式的系统参数,最后通过DIg SILENT软件建模仿真,基于连续潮流法对比两种并网方式系统正常工况下的静态特性,基于风电场故障扰动对比分析两者的暂态特性。仿真结果确定了多馈入直流并网用于新能源大量区域性接入的优越性,该拓扑能够平抑新能源波动,增加新能源消纳,减轻传统LCC直流送端对交流电网的依赖。

With the development of large-scale new energy, many regional energy bases appear, the traditional AC connected grid has small capacity, high loss, and great influence in the regional AC systems, VSC-HVDC is economic and stable, and can save the power transmission channel, large regional energy base paralleled in grids with multi-infeed VSC, then transmits electricity by LCC channel, and can solve the above problems. Firstly, we discussed the feasibility of mul- ti-infeed DC grid-connection, compared the AC/DC transmission technology, and evaluated the engineering application of the price. Then, we designed the topology of multi-infeed VSC grid and traditional AC grid, and calculated the system parameters of two systems. Finally, we used the DIgSILENT software to model and simulate, analyzed static characteristic of two grid-connected systems under normal working condition, and compared their transient characteristics by the fault disturbance of wind farm. Simulation results can determine the superiority of multi-infeed DC integration of new energy, and the topology can restraifl the fluctuation of new energy, increased consumption of new energy, and reduce dependence of AC power network for traditional LCC-HVDC.