Power quality problems in regional distribution networks in the Czech Republic

In the power company CEZ in the North Moravia region the monitoring of a number of selected parameters of the quality of electrical energy (harmonics, flicker and unbalance) is being done in cooperation with research laboratories of the Faculty of Electrical Engineering and Computer Science, VSB - Technical University of Ostrava. The monitoring is being done in a complex way in 59 feeding points 400 V, always in one week intervals, and at the same time on all voltage levels (HV, MV and LV). The whole cycle lasted for 3 years, and currently the fourth cycle of monitoring is realized. 3 full cycles enables comparing of the state after twice three years. In the paper, the results of the first, second and third cycle of the complex monitoring will be summarized together with the comparison of the changes of parameters after three years. In the second cycle of monitoring there were measured currents in the neutral conductor. The results of monitoring of harmonic components of current in the neutral conductor will be presented in the paper. The continuity of the supply of electrical energy gains importance in the market environment. That is why, attention is paid more and more to the monitoring of voltage drop and interruption in the distribution networks. Monitoring of these parameters is, of course, a long-term goal. Some knowledge in this area will be presented in the paper.