الفهرس 
1. IntroductionOnly 14 pages are availabe for public view
 |  | from | 90 |  |  |
| | | from | 90 | | |
Abstract
In this thesis, performance evaluation of modern current differential scheme used for line protection is investigated. Impact of fault resistance, fault type and location, abnormal power swings, line capacitances and sampling misalignment on the relay operation is deduced. The results have led to search for an alternative scheme which is less sensitive to sampling misalignment and time synchronization. This is cured by a novel fault detection concept for line protection introduced in this thesis. In this novel concept, the difference and average quantities for phase active and reactive power entering and leaving the line are compared. Performance of the developed detector is computed under sampling misalignment as compared with conventional current differential approach. This computation is carried out via simulating by (EMTP). The detector sensitivity for internal fault and stability for external fault are examined. The real time algorithms and required logics of the proposed differential power detector are developed and examined. Then, the setting rules for active and reactive power domains are proposed and tested for miscellaneous fault and normal operation cases. The real time test cases show efficacy of the proposed detector operation as it responds to system faults in a portion of the cycle and the detector is less sensitive to possible time synchronization errors. It would be fairly said that a new concept for line protection has been already launched.