基于奇异值分解的柔性直流输电系统短路故障识别方法

Short Circuit Fault Identification Method for Flexible DC Transmission System Based on Singular Value Decomposition

常规的输电系统短路故障识别方法以故障波形变化识别为主,受到输电系统运行状态的影响,故障识别存在一定的误差,为此设计了基于奇异值分解的柔性直流输电系统短路故障识别方法。提取柔性直流输电系统短路故障特征,包括正常运行状态的正序分量特征与故障状态下的负序分量特征,保留负序分量转化为频域形式,便于后续故障识别。使用奇异值分解识别输电系统短路故障区间,将故障区间分为区外故障识别与区内故障识别两部分,利用奇异值的稳定性作为故障区间的识别依据,从而实现短路故障的精准识别。经仿真实验验证,该方法具有较高的识别精准度。

The conventional methods for identifying short circuit faults in power transmission systems mainly focus on identifying changes in fault waveforms,and are inadequate in identification accuracy owing to the influence of transmission system′s operating status.Therefore the present work proposed the design of a short-circuit fault identification method for flexible DC transmission systems based on singular value decomposition.The short-circuit fault characteristics of the flexible DC transmission system,including positive sequence components of normal operating state and negative sequence components of faulty state,were obtained by feature extraction and converted into frequency domain form,in which the negative sequence components were retained,for subsequent fault identification.The singular value decomposition was introduced to identify short circuit fault interval of transmission system and divide it into two parts,i.e.,external fault identification and internal fault identification according to the stability of singular values,thus achieving accurate identification of short circuit faults.The method was verified by simulative experiments to have satisfactory identification accuracy.