单相重合时序对发电机频率特性的影响分析

Influence of Single-phase Re-closure Sequence on the Generator Frequency

发现交-直流并联系统中单相重合时序对发电机频率有较大影响。建立交-直流并联系统模型,在交流输电线路发生单相接地短路故障时,在单相重合时存在两种故障即单相断线故障和单相接地故障,形成双端口的故障网络。利用双端口理论、叠加原理、ward等值法和不对称分量法,由此得到两种不同重合闸时序下的发电机频率的变化规律,据此实现对发电机频率变化轨迹进行量化评估,从而得到发电机的暂态频率度,选取重合时序暂态频率稳定度较大者作为最优重合方案,以此得出提高发电机的稳定运行。并采用PSD-BPA软件对2016年南方电网进行仿真验证。

Significant influence of single-phase re-closure sequence on the generator frequency has been discovered in AC-DC system.AC-DC parallel system model was built,single-phase re-closure sequence has two faults when single-phase earth fault happens,single-phase earth fault and single phase line-open fault,to form two-port network fault.by using two-port network theory, superposition principle,ward equivalent method and asymmetric component method,The variation of the generator frequency were deduced under different re-closure sequence.Hereby,implement variation of the generator frequency quantitative evaluation.Accordingly,to obtain the generator frequency variation,Choose the maximum transient frequency of re-closure sequence as the optimal decision,enhancing and maintaining generators stability in power system. PSD-BPA software was used to simulate t2015 Southern Power Grid system.