多能互补发电系统故障识别与测距方法

Fault Identification and Location Method of Multi-energy Complementary Power Generation System

随着大量新能源的接入,使得多端柔性直流系统(modular multilevel converter based multi-terminal direct current, MMC-MTDC)故障特征愈加复杂,快速准确的故障识别与测距是亟需解决的关键难题之一。为此,提出了一种风-光-储-蓄互补发电站经柔性直流输电外送系统故障识别与测距方法。首先,搭建风-光-储-蓄互补发电站经柔直外送系统,在此基础上,提出了一种Teager能量算子能量熵的新方法,利用测量点正负极Teager能量算子能量熵的比值构建故障选极及区段识别判据。接着,针对已识别的故障线路,提出变分模态分解(variational mode decomposition, VMD)与Teager能量算子(teager energy operator, TEO)相结合的故障测距方法。最后,利用PSCAD/EMTDC进行仿真,结果表明所提识别方法可以准确判断故障所在线路,所提测距方法能在故障发生2 ms时间窗内实现故障测距,误差率不超过2.55%,并具有较高的耐过渡电阻能力。

With the access to a large number of new energy sources,the fault characteristics of multi-terminal HVDC based on MMC(MMC-MTDC)become increasingly complex.One of the key problems that urgently needs to be solved is the fast and accurate fault identification and fault location.To this end,a fault identification and location method for wind-photovoltaics-electrochemical energy storage-pumped storage hydropower complementary power plant transmitted by flexible DC transmission was proposed.Firstly,the flexible transmission system of the wind-solar-storage-storage-complementary power station was constructed.Based on this,a new method of Teager energy operator energy entropy was proposed,and the ratio of Teager energy operator energy entropy of positive and negative poles of measurement points was used to construct fault pole selection and section identification criteria.Then,a fault location method combining variational mode decomposition(VMD)and Teager energy operator(TEO operator)was proposed for the identified fault lines.Finally,PSCAD/EMTDC was used for simulation.The results show that the proposed identification method can accurately determine the fault line,and the proposed fault location method can realise fault location within 2 ms time window of fault occurrence.The error rate is not more than 2.55%,and it has strong ability to withstand transition resistance.