By increasing the number of consumers with non-linear characteristics that input the network with higher harmonics and with other disorders of power quality (voltage dips, voltage fluctuation, supply interruptions, increase of voltage, signal voltages, etc.) comes the negative impact on the electrical opposition both in industry and in households. By monitoring the voltage quality indicators and by analyzing them, we are trying to find a problem and solutions for them to be suppressed. The first part of thesis describes all the main indicators of the quality of electricity and their essential characteristics. The second part presents and analyzes the results of measurements of voltage quality on a dairy farm Topolik under standard EN 50160 for a period of seven days. For measuring we used network analyzer Fluke 1745 which was coupled to the main distribution bord MD photovoltaic power Topolik.