HPP “Djerdap 2“ is the second joint Serbian-Romanian hydropower plant on the Danube River. It was built on 863rd km of Danube from the confluence into the Black Sea on profile Kusjak-Ostrovul Mare. Just as HPP “Djerdap 1”, this system is a complex and multi-purpose hydrotechnical facility. It consists of power plant, two additional power plants, two spillway dams and two navigation locks. Each side, Serbian and Romanian, owns one of the above facilities. Basic power plant, as a structural unit, is divided into two equal sections, so that each side can unobstructedly use its part of the system.
Serbian hydropower plant “Djerdap 2“ has a total of ten generators, eight in basic power plant, with two additional generators in additional power plant. Total installed power of ten hydropower turbine generators is 270 MW. The operation of the first generator commenced back in 1985, on 12th of April.
Generators on hydropower plant “Djerdap 2“ are specific in relation to other Serbian power plants. Installed turbines are horizontal in-pipe turbines with Kaplan impellers. Generators are installed horizontally and placed within the capsule of the unit around which water flows from the water passage during the electric power generation. The specificity of the generator consists in water-cooled coils of stator and rotor. Even though the power is not considerable, the diameter of the impeller of these turbines is 7.5m, which ranks it on the second place in Serbia in terms of the dimensions, right after the turbine of HPP “Djerdap 1“.
After almost 40 years of use, the main and auxiliary equipment of hydropower plant are planned for reconstruction. The planned works are aimed at extending the useful life of the power plant, increasing the safety of its operation and energy efficiency.
The Romanian side with its 10 generators entered the phase of major overhaul earlier. Major overhaul of the Romanian hydropower plant included replacement of the impeller blades, which, apart from the extension of the useful life led to the increase in usability of the generator, of the nominal flow and power and, consequently, of the total capacity of the hydropower plant.
EPS signed a contract with Energoprojekt Hidroinzenjering on the preparation of Concept Design solution, Feasibility Study with Schematic Design and tender documentation for the upcoming reconstruction, modernisation and increase of capacity on the Serbian side of HPP “Djerdap 2”.
So far, Energoprojekt Hidroinzenjering has completed the design phase, i.e. prepared Concept Design and Feasibility Study with Schematic Design. Completion of contractual obligations, i.e. preparation of tender documentation is to be realised in the subsequent period. In the long term, the commencement of reconstruction on this project for Hindoinzenjering opens the possibility for a series of new additional potential projects.
Schematic Design for the reconstruction provides for rehabilitation of the parts and assemblies of the turbine and generator which can be retained, as well as replacement of specific parts where replacement with new parts is estimated to be cheaper than the reconstruction of the existing ones. The planned duration of the works on the reconstruction for the project with approximate value of 200 million euros is 15 years. Hence, the reconstruction of the last generator will be completed after 2040. By that time, the expected useful life even of the equipment on the youngest generator commissioned in 2000 will have expired.
Reconstructed generators will achieve higher levels of usefulness than the previous ones. Installed flow of the generator will be increased from current 425 m3/s to 475 m3/s, which ensures the increase of the total installed capacity of Serbian and Romanian power plant from 8,500 m3/s to impressive 9,500 m3/s. This change will enable higher production to hydropower plants, since in the period of high inflow from the Danube, hydropower plant will be capable to pass greater quantity of water through its turbines. Additional effect is the increased installed power of hydrogenerator which is increased from 27 MW to 32 MW. Other auxiliary equipment and systems will be replaced with new state-of-the-art equipment.
All of the above shows that the reconstruction of HPP “Djerdap 2“ is an extremely complex, demanding and long-standing project. Taking part in the project of reconstruction is primarily a great challenge for Hidroinzenjering, but also an honour, Energoprojekt writes.
