含多端柔性直流互联的交直流电力系统静态安全分析

含电压源换流器的多端直流系统在工作原理及控制方式上与常规直流系统存在本质区别,现有静态安全分析无法直接对含多端柔性直流的交直流系统分析计算。文中以传统交流电网静态安全分析为基础,首先,提出了多端柔性直流混联系统的交直流静态安全分析计算框架,阐述了功能实现方法及采用的关键技术。然后,在预想故障计算中考虑了交直流电网运行条件变化情况,保证计算结果与实际电网运行状态一致,提高了静态安全分析计算的准确性。最后,通过构建含四端柔性直流的交直流混联系统仿真模型,验证了算法的有效性和实用性。

Static Security Analysis of AC/DC Power System with Multi-terminal Flexible DC

The work principle and control mode of the multi-terminal DC system with voltage source converter(VSC-MTDC)are essentially different from the conventional DC system. The current static security analysis cannot directly analyze and calculate the AC/DC system with VSC-MTDC. Firstly, a calculation framework for AC/DC static security analysis of VSC-MTDC/AC hybrid system is proposed based on the traditional static security analysis of AC system, the adopted functional realization method and key technologies are described. Then, in the calculation of expected faults, the change of operation conditions of AC and DC power grids is taken into account to ensure that the calculation results are consistent with the actual operation conditions of power grids, which improves the accuracy of static security analysis and calculation. Finally, hybrid AC/DC system with four-terminal flexible DC system is established to verify the efficiency and practicability of the proposed method.