Sommer - Protective Relaying Dept. - SIEMENS AG. (Germany)

This paper treats the increase of availability of power transmission networks by upgrading the availability and information output of the installed protection equipment. A reliable protection is essential for highest availability of the power - system , Detailed information gained from the protection allows fast and exact analysis of system faults and helps prevent further damage by carrying out preventive maintenance in time. This can be achieved by installation of microprocessor-based protection equipment with its selfmonitoring features and significantly increased amount of information available for fast system fault analysis.