Combined Fault Detector and Faulted Phase Selector for Transmission Lines Based on Adaptive Cumulative Sum Method

In this paper, a novel approach is proposed for fault detection in transmission lines. This idea is based on the adaptive cumulative sum method (ACUSUM), whose structure is adaptive with the current passing through the corresponding line. The proposed ACUSUM algorithm can detect even low magnitude faults with high resistances. By using the proposed method, just a few milliseconds after fault inception, the fault detection unit permits the main protection algorithm to become activated. Moreover, ACUSUM output indices can discriminate faulted phases within only 1 ms after fault registration. This new faulted-phase selector can also be applied to double-circuit transmission lines to detect cross-faults as well as intercircuit faults. The results have shown that the proposed method has good performance in speed and accuracy as a combined fault detector and faulted-phase selector algorithm.