【作者】 王利；

【导师】 同向前； 段建东；

【作者基本信息】 西安理工大学 ， 电力系统及其自动化， 2009， 硕士

【摘要】 近年来,随着电力系统的迅速发展,我国电网呈现出大容量、远距离、高电压的发展趋势,对电网运行的稳定性提出了更高的要求。快速切除故障不仅有助于提高输电线路的传送功率,更重要的是能够增强电力系统的暂态稳定性。因此,具有高速甚至是超高速动作特性的行波保护成为未来继电保护设备的发展方向之一。针对目前单端型行波保护存在的主要问题是反射波的识别。本文提出一种新的高压输电线路的单端行波保护方案,只需要识别行波初始波波头。对不对称接地故障,本文通过对接地故障时零模和线模行波传输规律的分析,提出模量波速度差异的行波保护算法,形成了一种不对称接地故障的行波保护方案。对非接地故障,本文在分析输电系统频率特性的基础上,分析了边界条件对电压行波的衰减特性,用电压行波到达测量点的电压经过贝杰隆模型反推到故障点的电压和附加电压源大小的比率大小形成判据来区分区内外故障,提出了一种非接地相间保护方案,并且此方案也适用于三相短路保护。采用PSCAD/EMTDC电磁暂态仿真软件搭建了两个的500kV超高压输电线路模型,对不同故障距离、不同故障类型、不同故障过渡电阻等多种故障情况进行了大量的仿真,并利用MATLAB处理仿真数据,对算法进行验证,仿真结果表明了本文所提出单端行波保护算法的有效性。更多还原

【Abstract】 Power system in China develops very fast in latest years, and the trend of large capacity, long distance, and high voltage is formed, which demands higher transient stability for power system. Clearing the faults rapidly is an effective method not only to increase power transfer but also to improve transient stability of transmission system. So the transient based protection principle with high speed even ultra-high-speed operating performance becomes one of the development directions of power system protective relaying.The identification of reflection wave is the primary trouble of the existing single-ended traveling-wave protection schemes. The paper proposes a novel single-ended protection for EHV/UHV transmission line, which only needs initial traveling wave. For unsymmetrical grounded faults, the paper present a new protection scheme based on the vilocity gap between aerial-model and zero-model through analyzing aerial-model and zero-model traveling wave propagation rule. Form a new kind of traveling wave grounded protection programs. For ungrounded faults. The frequency characteristics of transmission line are analyed. And the attenuated effcet of boundary conditions on Voltage traveling wave is considered. The fault voltage is calculated by Bergeron model based on the voltage of fault point.Then the amplitude of voltage is Compared to the additional voltage, and ratio is used to distinguish an internal or external fault. Simulation results show that the protection method proposed is also suitable for three-phase faul.Two simulation models of 500kV extremely high voltage transmission systems are established on the platform of PSCAD/EMTDC. A lot of simulations about different fault conditions such as fault location, fault resistance, fault type and fault inception angle are carried out, and the simulation data is treated to validate the algorithms with MATLAB. The simulation results prove that the new algorithms are correct.更多还原