BS EN 60255-121:2014 PDF

What is BS EN 60255-121 - Functional requirements for distance protection about?

BS EN 60255-121 is a British standard as a part of IEC 60255 series that specifies minimum requirements for functional and performance evaluation of distance protection function typically used in, but not limited to, line applications for effectively earthed, three-phase power systems. BS EN 60255-121 also defines how to document and publish performance tests. BS EN 60255-121 covers a distance protection function whose operating characteristics can be defined on an impedance plane and includes specification of the protection function, measurement characteristics, phase selection, directionality, and starting and time delay characteristics.