The task of this thesis was to examine the issue of protecting the power system from lightning strikes using metal-oxide surge arresters. Attention had to be paid to the selection of arrester characteristics and installation location. Chapter 2 describes the overvoltages that occur in the system and that pose a danger to the system and electrical elements. Chapter 3 presents the characteristics of MO surge arresters. The principle of operation and the protection zone are described, which is approximately similar for all types of arresters. Specifically, for MO arresters from ABB, their construction and the main division into EXLIM and PEXLIM types of MO arresters are presented. The current-voltage characteristic is presented, which is very specific due to its pronounced nonlinearity, which is also a great advantage of MO surge arresters over silicon carbide surge arresters. The third chapter also presents other characteristics of surge arresters that are very important for selecting surge arresters. Chapter 4 presents the procedure for selecting MO surge arresters, which is applied in Chapter 5, which presents specific examples of selecting MO surge arresters for 110 kV and 220 kV plants.