Considering the SARS-COV-2 situation and stay in Bosnia and Herzegovina, there was an opportunity to cooperate in the preparation of a study and project documentation for testing pumped hydropower plant Čapljina. Collaboration on the study completed the overall picture of knowledge of the power system in practice. Voltage change (increase) control is unquestionable in terms of security and quality of electricity supply. Communication systems in the control and regulation service, in particular peak load and network losses, have facilitated access to network testing without going out into the field and thus reduced additional costs. The system operator is responsible for the management of voltage and reactive power in the transmission network of the power system, and has the obligation to maintain the voltage within the defined limits. The transmission network of Bosnia and Herzegovina is constructed in such a structure that the transmission lines are underloaded and from the moment of commissioning, there are problems with voltages. Compensatory stimulated operation of the plant greatly contributes to the regulation of voltage in the power system, as well as the disconnection of the transmission line, which is underloaded. The analysis of the compensatory operation of the Čapljina pumped hydropower plant in the regulation of voltage conditions, which has a significant impact in the electricity network, clearly shows the regulated voltages in parts of the electricity system. The measured voltage values show that the compensating mode of operation has an impact on the voltage reduction in parts of the power system. This confirms the fact that the issue of voltage conditions and Q/V regulation is of a local character, that is, that for good system Q/V regulation, control resources should be properly distributed throughout the system.