智能变电站行波能量比较式快速母线保护研究

Fast and reliable busbar protection is an important support for the safety of substation.The traditional traveling wave busbar protection possesses the very fast operation speed, but its reliability is low. With the development of related technologies and application of advanced mathematic tool, it is time to study excellent traveling wave busbar protection. For the busbar in the smart substation, this project will present a novel identification mehod for the fault direction based on the energy comparison of traveling waves, which solves the questions of traditional traveling wave protection influenced by busbar structure and fault conditions. Applying this method in the busbar protection, the busbar protection based on the energy comparsion of traveling wave is studied; To improve the reliability of busbar protection based on traveling wave, the project explores the identifecation criterions based on waveform integral for lightning stroke and circuit breaker operation, meanwhile, using S transform technique which has a analysis ability in the time- and frequency-domaion, the identification methods for the high-frequency disturbed signals will be considered; According to the technique characteristics of the smart substation, the schemes of extra high speed busbar protection and the process bus fitting for the traveling wave based busbar protection will be designed; A fast protection device sample based on the energy comparison of traveling waves will be manufactured, which will establish a foundation of theory and technique for the practicality of the traveling wave based busbar protection in smart substations. The proposed identification method for fault direction and novel theory of busbar protection based on the energy comparison of traveling waves can be used in the extra-high-speed line and busbar protections, which have a great theoretic significance and practical engineering value.

快速可靠的母线保护是变电站安全运行的重要保障，传统的行波母线保护动作速度极快，但可靠性较低。随着相关技术的发展及高级数学工具的应用，研究性能优异的行波母线保护具备了条件。针对智能变电站母线，研究行波能量比较式故障方向识别方法，解决传统行波保护受故障条件和母线结构的影响问题，将该方法应用到母线保护中，提出基于行波能量比较的母线保护新原理；为提高行波母线保护的可靠性，研究基于行波波形积分的雷击识别判据和开关操作识别判据，同时利用具有时频分析能力的S变换技术，研究高频干扰信号的识别新方法；根据智能变电站的技术特征，设计行波能量比较式母线保护方案及适合行波母线保护的过程总线；研制行波能量比较式快速保护的实验室样机，为智能变电站行波母线保护的实用化奠定理论和技术基础。提出的行波能量比较式故障方向识别方法和母线保护新原理，可应用于高压电网超高速线路保护和母线保护，具有重要的理论意义和工程应用价值。

变电站母线是电网功率汇集和重新分配的重要节点，快速可靠的母线保护是变电站安全运行的重要保障。目前广泛应用的母线差动保护尽管可靠性高，但要求采样数据同步，而且受区外故障CT饱和影响，动作速度一般在10ms以上。常规的行波母线保护虽然动作快速，但保护的可靠性较低。对此，项目以智能变电站母线保护为研究对象，研究了鲁棒性强、不受CT饱和影响、可靠性高、动作快速的三种新型母线保护原理；设计了母线保护方案；研制出了快速母线保护样机。主要成果为：（1）提出了积分型行波故障方向识别判据。该判据根据故障后较短时间内正、反向行波积分值的大小识别故障方向，由于采用了方向行波的积分值代替了初始行波的幅值，极大的提高了识别判据的可靠性。（2）提出了一种方向行波波形积分式快速母线保护方法。分析表明，母线区内外故障时，在故障后较短时间内所有出线上的正、反向行波积分值的大小存在差异，据此特征构建了母线故障识别判据，仿真结果验证了该原理的正确性。（3）提出了基于故障分量均值积的快速母线保护方法。根据母线区内外故障时，在较短时间内所有出线上的故障分量电压和电流均值积的符号差异，构造了母线故障识别判据，仿真结果验证了该判据的有效性。（4）提出了一种新型极性比较式快速母线保护方法。经研究，当母线内部故障时，在特定时间内所有出线上故障分量电流积分值的极性相同，而某一出线故障时，故障线路和其他正常线路上的故障分量电流积分值的极性相异，由此构造了母线保护判据，仿真结果证明了该判据的正确性。（5）基于方向行波波形积分式母线保护原理，研制出了集中式高速母线保护样机。动模试验和RTDS闭环测试表明，保护样机能正确识别各种区内故障，动作时间基本在4ms左右；而区外故障保护可靠不动。此外，CT饱和、开关动作对保护没有任何影响。. 上述成果为实现高压输电线路/母线快速保护原理与相关技术奠定了坚实的基础，具有重要的理论价值和良好的工程应用前景。