부산대학교 도서관

During islanded mode, the fault current seen by the relay is less as compared to the system in a grid-connected mode. Due to this, the conventional overcurrent relay faces protection challenges, such as relay miscoordination, delayed operation, or failure (blinding) in relay operations. This article proposes a relaying scheme, which uses a support vector machine (SVM)-based classification approach to solve the protection issues. The algorithm integrates the merits of both the radial basis function (RBF) and the multiclass Cubic SVM classifier. The RBF classifier can identify the relay jurisdiction and helps prevent false tripping. The multiclass cubic classifier has been designed to find the SVM class with appropriate relay tripping time. Without using any extensive communication facility, the proposed scheme coordinates the relays and maintains the coordination time interval (CTI) within the desired limits. Irrespective of the mode of operation and configuration of the system, the tripping time and CTI value of the SVM relay is better as compared with the conventional overcurrent relay. The decision function of both classifiers is simplified and programmed in a 200-MHz 32-bit microcontroller. The prototype of the proposed relay is tested on a 400-V four-bus laboratory-type distribution system by creating faults at different locations. The results obtained indicate the ability of the proposed method to perform the real-time operation in a microcontroller-based hardware platform.