Matshidza, R.Bartylak, A.Zivanovic, R.2007-08-142007-08-142005CIRED : 18th International Conference and Exhibition on Electricity Distribution, Lingotto Conference Centre, Turin, 6-9 June 2005 : technical reports : vol. 3, pp. [78]-8208634152960537-9989http://hdl.handle.net/2440/36846© 2005 Institution of Engineering and TechnologyESKOM has relied primarily on impedance-based measurement protection relays for the protection of EHV transmission lines. One of the main disadvantages of a distance relays is the limited fault resistance measurement capability. There are currently more than 20 relay types applied as transmission line protection on the ESKOM's transmission network with the most common types of characteristic being mho and polygonal characteristics.enConference paper002006567410.1049/cp:200511782-s2.0-2864444533049612