In recent years, there was increased use of advanced light sources with electronic control gear (LED Sources). This inevitably affects the generation of harmonic pollution in the power grids for lighting. The report presents a study of harmonic pollution in industrial power grids for lighting. The aim of the study was to analyze the impact of modern LED sources on the quality of energy in industrial lighting power grids. Since it is usually in the industry, lighting networks have a large number of luminaires and high power, the impact of the generated harmonics on the power supply parameters is noticeable. A particular lighting facility of a medium-sized industrial building was investigated. The study is done with the operation of the lighting system. Various electrical parameters were measured using a network analyzer. Results are displayed after processing the measured data. There are made appropriate conclusions from the study.