直流输电工程在长期发展中形成相对固定的控制策略,完善该策略对提高交直流混联电网的稳定性有重要意义。近年来,使用机电–电磁混合仿真技术进行稳定分析,在大电网交流侧某些严重故障下,多条基于电网换相换流器的特高压直流(ultra-high...直流输电工程在长期发展中形成相对固定的控制策略,完善该策略对提高交直流混联电网的稳定性有重要意义。近年来,使用机电–电磁混合仿真技术进行稳定分析,在大电网交流侧某些严重故障下,多条基于电网换相换流器的特高压直流(ultra-highvoltageDCbasedonline commutatedconverter,LCC-UHVDC)工程均出现了持续大幅度功率振荡,表明现有控制策略需要一步完善。该文介绍了各UHVDC工程中出现的相似功率振荡现象,并以某工程为例,深入分析直流控制器中换相裕度面积计算(commutation margin area calculation module,AMINCALC)、设置最大熄弧角输出(maximumarcanglelimiteddirect outputmodule,GAMMA0)及低压限流(voltagedependent current order limiter,VDCOL)等多个控制环节共同诱发功率振荡的机理;研究抑制该类直流振荡可能的控制措施及实用的控制优化方案。实际电网的仿真证明了该方案的有效性。展开更多
Distinction of weak and strong AC grids for emerging hierarchical-infeed LCC-UHVDC systems is important for planning and operation departments. However, accuracy of earlier distinction methods is limited as they were ...Distinction of weak and strong AC grids for emerging hierarchical-infeed LCC-UHVDC systems is important for planning and operation departments. However, accuracy of earlier distinction methods is limited as they were developed by empirical reasoning without rigorous theoretical analysis. Hence in this letter, hierarchical-infeed interactive effective short-circuit ratio (HIESCR) index is first used for strength evaluation of HIDC systems with complex inter-inverter interactions considered. Boundary HIESCR (BHIESCR) is also introduced in the proposed distinction method of weak and strong AC grids. That is, weak (or strong) AC grids are, respectively, identified when HIESCR is less (or greater) than BHIESCR. Second, it is shown BHIESCR remains almost unchanged as 3.0 versus various system parameters and rated operation variables based on rigorous theoretical analysis. This salient feature makes the proposed method more accurate than earlier methods. Finally, the proposed method is validated by simulations based on the PSCAD/EMTDC program.展开更多
文摘直流输电工程在长期发展中形成相对固定的控制策略,完善该策略对提高交直流混联电网的稳定性有重要意义。近年来,使用机电–电磁混合仿真技术进行稳定分析,在大电网交流侧某些严重故障下,多条基于电网换相换流器的特高压直流(ultra-highvoltageDCbasedonline commutatedconverter,LCC-UHVDC)工程均出现了持续大幅度功率振荡,表明现有控制策略需要一步完善。该文介绍了各UHVDC工程中出现的相似功率振荡现象,并以某工程为例,深入分析直流控制器中换相裕度面积计算(commutation margin area calculation module,AMINCALC)、设置最大熄弧角输出(maximumarcanglelimiteddirect outputmodule,GAMMA0)及低压限流(voltagedependent current order limiter,VDCOL)等多个控制环节共同诱发功率振荡的机理;研究抑制该类直流振荡可能的控制措施及实用的控制优化方案。实际电网的仿真证明了该方案的有效性。
基金supported in part by the National Natural Science Foundation of China(51907067)in part by the Industrial Research Chair Program of the Natural Sciences and Engineering Research Councilof Canada。
文摘Distinction of weak and strong AC grids for emerging hierarchical-infeed LCC-UHVDC systems is important for planning and operation departments. However, accuracy of earlier distinction methods is limited as they were developed by empirical reasoning without rigorous theoretical analysis. Hence in this letter, hierarchical-infeed interactive effective short-circuit ratio (HIESCR) index is first used for strength evaluation of HIDC systems with complex inter-inverter interactions considered. Boundary HIESCR (BHIESCR) is also introduced in the proposed distinction method of weak and strong AC grids. That is, weak (or strong) AC grids are, respectively, identified when HIESCR is less (or greater) than BHIESCR. Second, it is shown BHIESCR remains almost unchanged as 3.0 versus various system parameters and rated operation variables based on rigorous theoretical analysis. This salient feature makes the proposed method more accurate than earlier methods. Finally, the proposed method is validated by simulations based on the PSCAD/EMTDC program.
