ABSTRACT

Protection engineers and academicians are continuously working towards better relaying for modern transmission structures. This has become a requirement because transmission structure, nowadays, is being updated with new technologies, e.g. flexible AC transmission system devices. In this paper, it has been observed that the differential DC plays an important role in distinguishing the internal and external faults. A criterion is then developed based on this unique feature of the differential DC for the identification of faults in modern transmission lines. The performance of the proposed criterion has been tested with the help of simulation study carried out using EMTDC/PSCAD software for a variety of fault types with variations in fault location, fault resistance, fault inception angle, and compensation level. Furthermore, the performance of the proposed algorithm is also investigated for several rare conditions such as evolving faults, cross-country faults, noise in measurement, and measurement error. The results prove that the scheme is selective, accurate, and robust for uncompensated and series-compensated lines while it is accurate for low resistance faults in the case of a shunt-compensated line.

摘要

保护工程师和院士们不断致力于为现代传输结构提供更好的继电保护。这已成为一项要求，因为当今的传输结构正在通过新技术进行更新，例如灵活的交流输电系统装置。本文观察到差动直流在区分内部和外部故障方面发挥着重要作用。然后，基于差分直流的这一独特特征，开发了一种标准，用于识别现代输电线路中的故障。借助使用 EMTDC/PSCAD 软件对各种故障类型（故障位置、故障电阻、故障起始角和补偿水平存在差异）进行的仿真研究，测试了所提出准则的性能。此外，还针对几种罕见情况（例如演化故障、跨国故障、测量噪声和测量误差）研究了所提出算法的性能。结果证明该方案具有选择性、准确性、