scholarly journals Technology of welding and repair works of hydropower plants units

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Mykola Kakhovskyi ◽  
Yurii Kakhovskyi ◽  
Anton Ievdokymenko

In the course of long-term operation of hydroelectric units, they are subject to wear and tear, which negatively affects the power generating capacity of the hydroelectric power station. The existing repair technology provides the restoration of the geometric dimensions of the impeller chamber of the hydraulic unit using an austenitic cladding layer. However, this technology is characterized by the occurrence of cracks and delamination of the deposited layer during post-repair operation, which is negatively reflected in the production cycle of electricity. A new technology and welding consumables have been proposed for repair and restoration works of hydroelectric units at hydroelectric power plants, providing an increase in the quality level, high characteristics of hydroabrasive and cavitation resistance, and increasing of working period of hydroelectric power plants. Inspection of the body of the hydraulic unit was carried out, defects were identified and classified, the reasons for their occurrence were analyzed. The research results make possible to optimize the alloying system of the deposited metal, to determine the optimal welding mode, to reduce the amount of the martensite component and to develop new filler materials and the technology for welding and repair works of hydroelectric power plants.

Author(s):  
Rúbia Fantin Cruz ◽  
Stephen K. Hamilton ◽  
Hans M. Tritico ◽  
Ibraim Fantin‐Cruz ◽  
Daniela Maimoni Figueiredo ◽  
...  

1946 ◽  
Vol 65 (4) ◽  
pp. 151-159 ◽  
Author(s):  
A. H. Frampton

Author(s):  
Petro Lezhnyuk ◽  
Iryna Hunko ◽  
Juliya Malogulko ◽  
Iryna Kotylko ◽  
Lіudmyla Krot

Urgency of the research. Current trends of distributed generation development in Ukraine indicate a rapid generation in-crease from renewable energy plants. Most developed countries gradually refuse from the fossil fuels use and invest more and more to the “green” energy. Therefore, there is a need for a detailed study of the operation conditions of distributed energy sources due to their instability, as well as the processes that arise in distribution electric networks with diverse types of distributed energy sources. Target setting. In the producing process of power energy by distributed energy sources due to the increase in their num-ber, there are situations where several renewable sources of energy operate to only one system of buses. Thus, such distributive networks acquire the features of a local power system, which complicates the control process of such systems, and also there is a problem with the electricity supply of consumers. Actual scientific researches and issues analysis. The analysis of publications suggests that in literature more attention is paid to studying the operating modes of solar power plants, or small hydroelectric power plants. However, almost no attention was paid to the study of their cooperation work. Uninvestigated parts of general matters defining. Only a few works are devoted to the study of the cooperation of the diverce sources of distributed energy sources in the local electrical systems. That is why, their impact on power distribution networks and on the grid in general has not been studied extensively. The research objective. In this article was considered the influence of asynchronous generators on small hydroelectric power plants on the operation modes of distribution electrical networks, and were investigated the processes that are occurring in local power systems with different types of distributed energy sources. The statement of basic materials. Based on the research results, was developed a computer model of a such system in the PS CAD software environment. Two solar stations and one small hydroelectric power station with an asynchronous generator were connected to the power supply. It was shown the simulation of two modes of operation: a joint operation of a small hydroelectric power station, two solar power stations and a power supply center; a joint operation of a small hydroelectric pow-er plant, two solar power stations and a power supply disconnected. Conclusions. As a result of computer simulation, it is shown that by switching on a small hydroelectric power plant with an asynchronous generator in the case of an emergency shutdown of centralized power supply, it is possible to restore the work of solar power plants, and thus partially or completely restore the power supply of consumers.


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