含多种限流设备的柔性直流电网RT-LAB实时仿真建模

Real-Time Modeling and Simulation of Flexible DC Grid with Various Types of Current Limiting Devices Based on RT-LAB

柔性直流电网具有"低惯性、弱阻尼"的特点,其故障电流上升速度快且峰值高。针对包含大量电力电子器件的限流设备不仅增加系统复杂性,同时也降低直流电网仿真效率的问题,提出不同限流设备的等效建模方法。首先,搭建包含多种限流设备的17端柔性直流输电网数字仿真模型;其次,依据单端口子模块等效建模方法,分别针对其中4种典型故障限流设备提出有效的等效建模策略;最后,基于RTLAB平台对17端直流电网数字模型进行实时化处理,完成实时模型的搭建。仿真结果显示,所提等效方法和所建实时仿真模型,可以实现对稳态、故障等多种工况的精确拟合。

Flexible DC grids have the characteristics of"low inertia and weak damping",and their fault current rises rapidly with high peak value.Current limiting devices usually contain a huge number of power electronic devices,which not only increases the complexity of the system,but also reduces the simulation efficiency of the DC grids.An equivalent modeling method is proposed for different current limiting devices,so as to improve the simulation efficiency of the model and meet the requirements of system design and operation analysis.Firstly,a digital simulation model of a 17-terminal flexible DC grid with various current limiting devices is built in this paper.Then,according to the generalized equivalent modeling method for single-port sub-module,an effective equivalent modeling strategy is proposed for four typical fault current limiting devices respectively.Finally,the digital model of 17-terminal DC grid is processed in real-time based on RT-LAB platform to complete the construction of the real-time model.The simulation results show that the proposed equivalent method and the real-time simulation model can accurately fit various working conditions such as steady-state and fault.