Mahmoud R A
Department of Electrical Power and Machines Engineering (PME), College of Engineering Science & Technology, Misr University for Science and Technology (MUST), 6Th of October City, Giza, Egypt.
Sci Rep. 2025 Aug 12;15(1):29552. doi: 10.1038/s41598-025-12832-8.
This paper presents an adaptive protection algorithm that adjusts the tripping characteristics of the differential relaying schemes in response to changes in CT saturation levels and DC component content of fault currents. Moreover, the main protection function differentiates between internal and external faults with or without CT saturation. This is accomplished by estimating the appropriate tripping characteristic slope using form and ripple factors calculated for the current signals measured at the entering and exiting terminals of the protected equipment. The modified approach aims to achieve automatic resetting to inhibit the relay operation during external faults and to avoid any delay or restriction of the relay operation during severe internal faults due to the presence of harmonics. Numerous cases, including various types of internal and external faults with or without CTs saturation and DC component, are carried out on a typical power system simulated using the ATP platform. The proposed algorithm can be performed utilizing the MATLAB software, which can receive current measurements from the ATP simulator. The simulation results manifest the functional efficiency of the suggested technique under diverse operating and fault conditions and its ability to discriminate fault location. Additionally, the response time of the suggested technique is roughly 10.0 ms in the event of internal faults, which is also appropriate for preventing the technique from functioning in the case of non-fault or external fault disturbances. Furthermore, it is able to recognize CT saturation conditions, assess the degree of current distortion, and select which feeder CT is saturated. Besides, the outcomes demonstrate the extreme simplicity, effectiveness, stability, accuracy, and reliability of the proposed algorithm. Quantitative findings from the extensive case studies indicate that the estimated ratios of the protection's accuracy, dependability, security, and reliability are greater than 99.40%. It is applicable to Smart Grids (SGs) and Substation Automation Systems (SAS), as the algorithm is one of the applications in digital protection relays/systems.
本文提出了一种自适应保护算法，该算法可根据电流互感器（CT）饱和水平和故障电流直流分量含量的变化来调整差动保护方案的跳闸特性。此外，主保护功能能够区分有或没有CT饱和情况下的内部和外部故障。这是通过使用为在被保护设备的进线端和出线端测量的电流信号计算出的波形系数和纹波系数来估计合适的跳闸特性斜率来实现的。改进后的方法旨在实现自动复位，以抑制外部故障期间的继电器动作，并避免由于谐波的存在而在严重内部故障期间对继电器动作造成任何延迟或限制。在使用ATP平台模拟的典型电力系统上进行了大量案例分析，包括各种有或没有CT饱和及直流分量的内部和外部故障。所提出的算法可利用MATLAB软件执行，该软件可接收来自ATP模拟器的电流测量值。仿真结果表明了所建议技术在各种运行和故障条件下的功能效率及其区分故障位置的能力。此外，在内部故障情况下，所建议技术的响应时间约为10.0毫秒，这也适合防止该技术在非故障或外部故障干扰情况下动作。此外，它能够识别CT饱和情况，评估电流畸变程度，并选择哪个馈线CT饱和。此外，结果证明了所提出算法的极度简单性、有效性、稳定性、准确性和可靠性。大量案例研究的定量结果表明，保护的准确性、可靠性、安全性和可靠性的估计比率大于99.40%。由于该算法是数字保护继电器/系统中的应用之一，因此适用于智能电网（SG）和变电站自动化系统（SAS）。
