Herbert Leopold GABRYŚ
Power industry in Poland in 2019... from the 2018 results and not only
Energy industry in Poland 2019 is a waiting time for the acceptance of the submitted draft concerning Polish energy policy until 2040. It is also time of turbulences resulting from decisions „freezing” energy prices for end-users on the level of June 2018. In the view of results achieved in 2018, the Polish power industry appears to be more advantageous in comparison with results from 2017. Adding together the incomes from the sales of four capital groups, they were bigger by 7,38% in relation 2018/2017 and by 28,58% in relation to the year 2010. The power industry in Poland is characterised by an already permanent trend to decrease energy consumption related to the economic growth. Comparison made between cross-border flows of electricity in the years 2010 and 2018 shows evident import dynamics. The share of renewable energy in total electricity production did not exceed 12,7%. And prices of electric energy in the TGE (POLPX) wholesale market have greatly increased.
Keywords: energy industry in Poland, energy industry financial results, the year 2019
Rafał CZAPAJ, Jacek KAMIŃSKI, Pablo BENALCAZAR
Neural networks for driving systems control – theoretical introduction
Described is the basic knowledge relating to biological neural networks, their models, activation function and learning methods applied in many areas including driving systems control. Properly selected and taught neural networks enable recovery of the inaccessbile by measurements variables of a driving system condition thanks to their identification on the basis of specified input and output object signals or on the basis of neuromodeling of a driving system. Presented here considerations were also extended by exemplary applications of artificial neural networks in some other areas like forecasting, analysis and classification of data as well as filtering of measurement signals.
Keywords: neural networks, driving systems control, artificial neural networks
Marta DROSIŃSKA-KOMOR, Natalia SZEWCZUK-KRYPA
Comparison of selected types of nuclear power plants with high-temperature gas-cooled reactors (HTGR)
Among many other interesting solutions of power plants, the USA, Russia and China offer the application of the so-called floating nuclear power plants. In this case the plants would be equipped with a high-temperature reactor of the HTGR type cooled with gas. Conducted were relevant deliberations and efficiency calculations for 560 MW units of a nuclear steam and a gas turbine power plants. Higher efficiency of the steam turbine does not denigrate the possibility to use both types of cycles depending on location and intended use of power plants situated on sea in the vicinity of a hard-to-reach land areas or islands.
Keywords: HTGR reactor, marine floating nuclear power plants, nuclear energy
Paweł FRĄCZ, Daria WOTZKA, Mirosław GRYSZPIŃSKI
Comparison of partial discharges distribution on the surface of ceramic and composite insulators
Presented are results of the research on surface partial discharges on MV ceramic and composite strain insulators. The research was conducted in constant environmental conditions. Measurement results were presented by the means of images of visible light superimposed on the UV range electromagnetic radiation emission generated by partial discharges.
Keywords: ceramic and composite MV strain insulators, research on the surface partial discharges
Paweł FRĄCZ, Szczepan PASZKIEL, Piotr SZPULAK
Acoustic measurement method of partial discharges of electric charges distribution on a dielectric surface
Presented is the methodology and results of investigations conducted by the method of acoustic emission of electric charges distribution on the surface of a pressboard, subject to temporary electrification with the safe voltage equal 0.8 of breakdown value, with the use of a specialized acoustic camera. Comparative analysis has also been done of the obtained results with the UV radiation emission measurement method. The results are presented in the form of spectrograms registered by the acoustic camera.
Keywords: measurement of partial discharges of electric charges distribution on a dielectric surface, acoustic measurement method, acoustic camera
Dawid CEBULA
Bearing damages in motors powered by inverters
Requirements that must be met by electric drives make them to develop dynamically. There evolve modern and innovative systems to control and power electric motors. The factor that is by far the most frequent cause of bearing damages is axial thrust on a motor shaft. In case of motors powered by inverters the most frequent cause of rolling elements damages is the occurrence of a bearing voltage. The flow of a current through bearings causes the phenomenon called electrical corrosion and also contributes to accelerated grease degradation. The process occurs both in generators and in motors. Bearing currents are only one of bearing damage causes but the one that is particularly important and requires undertaking various actions and preventive measures.
Keywords: bearings, motors powered by inverters, bearing damages
Jerzy TRZESZCZYŃSKI
Safety and availability of power equipment in the last phase of their operation
The last phase of the power unit period of operation, which should be planned more thoroughly than the previous ones. The end of resurs is usually not the result of consumed life of critical elements but legal requirements, which may be accompanied by deterioration of economic indicators. Technical conditions of power units in this phase of operation plays a fundament role, because safety and high availability should be ensured with limited expenditure on overhauls and diagnostics. More aggressive operation of such units may increase the chances of improving economic indicators provided that the maintenance costs are in the proper relation to the value of such production. This kind of operation of power units in its last phase of the resurs may be planned.
Keywords: safety of power equipment, technical conditions of power units, the last phase of the power unit period of operation
Tomasz GAWROŃSKI
Evaluation of the dynamic state of turbogenerator sets
The attention is paid to the appropriateness of adjusting the settings of security systems from exceeding the vibration limits based on the baseline values obtained from measurements during long-term operation individually for each direction in individual bearings.
Keywords: dynamic state of machines, bearing housing vibration, shaft relative vibration, standarts.
Jerzy TRZESZCZYŃSKI, Wojciech MURZYNOWSKI
Diagnostic supervision of conditional operation for damaged desuperheaters until their replaced or repaired
Diagnostic supervision of conditional operation for damaged elements is presented on the example of desuperheaters. In case of these desuperheaters, on internal surfaces, non-destructive tests have detected, endoscopically and ultrasound confirmed, indications of the nature of operational cracks. Such damages are practically unrepairable and prefabrication and replacement of damaged elements takes a lot of time. The methodology (diagnostic supervision of conditional operation) also works for damaged elements, for which replacement or repair becomes unprofitable due to the approaching end of their service life. The paper presents methodology of conditional supervision operation of steam desuperheater supported by the LM System PRO+® application with newly developed modules and algorithms for monitoring the progress of cracks in on-line mode.
Keywords: diagnostic supervision, conditional operation for damaged desuperheaters, LM System PRO+®
Ewald GRZESICZEK, Sławomir RAJCA, Piotr REICHEL
Diagnostics of power units TG sets operated in the flexible operation mode
Knowledge about TG sets current technical condition should be the basis for generation and overhauls planning especially nowadays when operating conditions of conventional units undergo significant changes and operating time of the oldest ones, but still very useful for the Polish power system, exceed 250 000 hours. The measure of a turbine technical condition are its availability, dynamic condition and efficiency. Power units, including turbines, have been working for some time now in the flexible operation mode. A shift in turbine operation from the basic work to a flexible mode causes a range of negative effects influencing reliability and operational safety of turbines. The sources of negative effects relating to steam turbines flexible operation mode may be seen in low-cycle fatigue, erosion and standstill corrosion. Frequent load changes in the range of rated power and technical minimum can cause damages relating to low-cycle thermo-mechanical fatigue (TMF). The most vulnerable to this type of damages are turbine rotors and the specially „favoured” parts of them are end glands and rotor central holes.
Keywords: power units, flexible operation, diagnostics of TG units