Ground impedance measurement on the ground system of HE Zakucac

Abstract

The Zakucac HPP is the largest hydropower plant in the Cetina River basin, located at the mouth of the Cetina River near Omis. It uses water from two distant reservoirs: Peruca and Busko Blato, which perform seasonal (Peruca) and annual (Busko Blato) equalization of watercourses. With these two reservoirs, the Zakucac HPP has the possibility of peak operation throughout the year. With a total installed capacity of nearly 500 MW, it is a key facility in the Croatian power system. The grounding of the switchgear, production facilities and facilities along the Gata basin are galvanically connected and form a single grounding system. Due to the possibility that the Zakucac HPP grounding system is galvanically connected to the grounding system of the wider consumer area of ​​Omis and Dugi Rat through known and unknown installations (water supply network, low-voltage network and similar installations), the RP 110 kV grounding system next to the Kraljevac HPP was selected as an auxiliary grounding system (current probe). This grounding system is far enough away to safely avoid overlapping potential funnels. Measurements on the grounding conductor of the HPP “Zakucac” were carried out by simulating a condition similar to a single-pole short circuit. The determination of the potential distribution was carried out along six directions. The measurement of the touch and step voltages at all locations, except for the gate chamber, did not record any significant values. Measurements on the grounding conductor of the Prancevici dam were carried out as if it were a medium voltage facility. The analysis of the measured data allows us to conclude that the HPP Zakucac, as well as the Prancevici dam, meets the technical regulations on grounding of power plants.

Stanko Milun

Full Professor

Faculty alumnus with a research focus in the development of measurement methods in high-voltage systems, signal analysis in electrical power systems, and the application of geoelectrical methods in energy infrastructure. Prof. Milun has been involved in numerous scientific projects, including those related to the optimization of grounding systems for high-voltage plants and the development of transient measurement methods. He has authored 38 scientific papers and over 150 professional studies.

Goran Petrović

Full Professor | Department of Electrical Measurements

Prof. dr. sc. Goran Petrović is a full professor at the Faculty of Electrical Engineering, Mechanical Engineering and Architecture in Split. His research interests include measurement of electrical and process quantities, analysis of geoelectrical and geothermal features of the soil, instrumentation for smart grids, measurement and application of synchrophasors. He is the author of numerous papers published in top-tier scientific journals and contributed to valuable international and national scientific projects.