Cyber security is a major concern due to global incidents of intrusion. The impact of the attacks on the electricity grid can be significant, resulting in the collapsing of the national economy. Electricity network is needed by banks, government security agencies, hospitals and telecommunication operators. The purpose of this research is to investigate the various types of cyber security threats, including ICT technologies required for safe operation of the smart grid to protect and mitigate the impact of cyber security. The modelling of cyber security using the Matlab/SimPowerSystem simulates the City of Tshwane power system. Eskom components used to produce energy, interconnect to the City of Tshwane power distribution substations and simulated using Simulink SimPowerSystem. / Dissertation (MEng)--University of Pretoria, 2017. / Electrical, Electronic and Computer Engineering / MEng / Unrestricted