Over several decades, power quality has become an increasingly important factor in electricity supply. This was because customers were becoming more aware of the quality of the electricity and because the electrical appliances were becoming more sophisticated and sensitive to voltage disturbances. In this progress, it has been neglected that certain appliances by themselves cause interference and broadcast them to the network. The transmission network is characterized by its participants. Therefore, solutions for maintaining the voltage quality on medium voltage or low voltage networks are not applicable in running the transmission network. A low-voltage system operator may disconnect a network user from the network if it adversely affects the surrounding network and other participants, but the transmission system operator does not have such authority because of the political and economic importance of the network user. In order to find a way to solve this problem, in the dissertation it was first necessary to thoroughly investigate the parameters of voltage quality on the entire transmission network of the Croatian electricity system. It was concluded that the allowable values of the parameters should be determined according to the voltage level at which they are measured, and not the same norm to determine the allowable values at all voltage levels. After that, the necessary device powers for correcting the values of the voltage quality parameters were made, in order to keep these parameters within the allowed limits at each node of the network. Based on this calculations, a proposal for a system of penalties, incentives and compensations was formed, which should be implemented to encourage all network users to reduce the potentially negative impact of their facilities on the of the network’s voltage quality. Finally, an algorithm was developed in the dissertation that treats all network users equally, in such a way that no one is withheld the right to electricity of guaranteed quality. The algorithm was verified on the examples of the actual transmission network, which confirmed that the legislation related to power quality should be supplemented with a system of penalties, incentives and compensation.