Electricity is treated as a commodity today. The quality of electricity, at all voltage levels, is strictly defined by international standards, the most important of which for our area is the European standard EN 50160. This standard should be briefly described in the diploma thesis and an analysis of the quality of electricity in the area of TS Dugopolje should be carried out based on the measurement of registered data. 110/10 kV/kV. It is also necessary to conduct an analysis of electricity consumption for four characteristic weeks.