Wide area differential protection system

This dissertation is concerned with the development of a new protection philosophy and methodology applicable to ship characteristic power systems (ac part) for fault detection and isolation. A wide area differential protection system and a fuzzy based differential alarm system are the applications of the theories developed in this dissertation.; In the introduction part, the dissertation studies the conventional protection techniques and analyzes a 'short-cable' problem associated with protecting a power system on board a ship. The differential method has been identified to have the most potential application in the ship area. The historical development of differential protection methods and differential protective relays are considered in the next chapter.; Subsequent chapters develop new differential theories oriented to the ship protection application: symmetrical component based differential fault characteristics analysis for an ungrounded ship power system, fuzzy differential fault factor, and differential ring fault detection/location principle; and investigate the most desirable fault detection and protection systems: a Fuzzy Based Differential Alarm System (FBDA) and a wide area differential protection (WADP) system.; The experimental section deals with the development and testing of the WADP system for time critical events. The simulation section deals with the development and testing of the FBDA system for not critical time events.; Finally, the issues on ship power system protection and an overall differential type protection system are discussed.