基于动态状态估计的特高压交流输电线路故障诊断方法研究

This project will propose a dynamic state estimation based fault diagnosis method of Ultra High Voltage AC (UHVAC) transmission lines. The purpose of this research is to quickly isolate the transmission line with fault and locate the fault after the fault occurs, in order to ensure safety of electric equipment and power system, to reduce the transmission line power outage time and to improve the reliability of power supply. The proposed method uses instantaneous measurements within the low and mid frequency band to achieve fault diagnosis in UHVAC transmission lines. Compared to legacy fundamental frequency phasor based methods, the proposed method considers more information from a wider frequency band. Compared to legacy transient traveling wave based methods, the proposed method does not need high frequency electric quantities, can fully utilize data acquisition systems inside smart substations and does not require additional data acquisition hardware. Prior to this research, we have preliminarily applied similar methods in various power system components including extra high voltage transmission lines, which proves the feasibility of this research. In this project, we will first build the accurate physical model of the UHVAC line within the low and mid frequency band. Afterwards, we will study the internal fault characteristics of UHVAC lines, and establish the protective relaying criterion based on the consistency index calculated from the dynamic state estimation algorithm. Next, we will build the relationship between the location of the fault and available measurements, and locate the fault by solving all the dynamic states of the UHVAC line using dynamic state estimation algorithm.

项目拟开展基于动态状态估计的特高压交流输电线路故障诊断方法研究，其目的是在线路故障发生后迅速隔离故障线路并定位故障，以保证电力设备及电力系统安全、减少线路停电时间、提高供电可靠性。该方法利用中低频段电气量信息完成故障诊断。与工频相量法相比，其考虑了宽频带的电气量信息；与暂态行波法相比，其无需高频电气量信息，充分应用智能变电站的数据采集系统，没有额外硬件投入。申请者在前期预研工作中已将该方法初步应用于包括超高压输电线路在内的多种电力系统元件，证实了本项目研究的可行性。本课题组将在前期工作的基础上，首先建立特高压交流线路中低频段精确动态物理模型；其次结合特高压交流线路区内故障特征分析，利用动态状态估计算法的一致性指标构建保护判据；最后建立特高压交流线路故障位置与测量值关系，采用动态状态估计算法求解线路的全部动态状态量信息实现故障定位。

项目开展了基于动态状态估计的特高压交流输电线路故障诊断方法研究，其目的是在线路故障发生后迅速隔离故障线路并定位故障，以保证电力设备及电力系统安全、减少线路停电时间、提高供电可靠性。该方法利用中低频段电气量信息完成故障诊断。与工频相量法相比，其考虑了宽频带的电气量信息；与暂态行波法相比，其无需高频电气量信息，充分应用智能变电站的数据采集系统，没有额外硬件投入。申请者在前期预研工作中已将该方法初步应用于包括超高压输电线路在内的多种电力系统元件，证实了本项目研究的可行性。本课题组在前期工作的基础上开展了进一步的研究。首先，构建了特高压交流线路中低频段精确动态物理模型，精确描述了线路健康状态与故障状态线路应满足的物理规律。其次，分析了特高压交流线路区内故障特征，并利用动态状态估计算法，提取测量值与健康线路精确模型之间的一致性指标，构建保护判据。再次，建立了特高压交流线路故障位置与测量值的关系，利用动态状态估计算法，求解线路的全部动态状态量，实现故障定位。最后，提出了改进的离散化方法与动态状态估计算法，进一步提升算法的有效性；并将该方法拓展至同塔双回的特高压交流线路中。大量仿真算例与硬件在环平台验证结果表明，所提出的继电保护判据能迅速可靠地切除特高压交流故障线路，动作时间为故障后数毫秒；所提出的故障定位方法能利用故障后数毫秒内的电气量信息，准确地计算出特高压交流线路的故障位置。