Razvoj i primena tehničkih dijagnostičkih metoda i opreme za praćenje i vođenje procesa; unapređenje opreme sa aspekta procesa koji se u njima odvijaju; savremena organizacija proizvodnje, metode i sredstva održavanja opreme.
Radovi odabrani za sesiju Konferencije pod nazivom: Eksploatacioni problemi termo/hidro/vetro i drugih elektrana
Dr.-Ing Roland Jeschke , Head of Numerical Calculations (MITSUBISHI HITACHI POWER SYSTEMS EUROPE GmbH, Schifferstraße 80, 47059 Duisburg, Germany)
Christian Kissling, Head of Sales (MITSUBISHI HITACHI POWER SYSTEMS EUROPE GmbH, Schifferstraße 80, 47059 Duisburg, Germany)
Abstrakt
Between 2012 and 2015 a Low NOx Rehabilitation was conducted by Mitsubishi Hitachi Power Systems Europe GmbH (‘MHPSE’ as Joint Venture successor of Hitachi Power Europe) at TPP Nikola Tesla A (‘TENT A’) Unit 5, property of PE Electric Power Industry of Serbia (‘EPS’), consisting of Mill Upgrade/Conversion, Low NOx RS®-Burner and Over Fire Air installation. The targets of the respective activities were: Increase Mill Capacity, improvement of grinding fineness, optimize operational behavior via skip of support oil for full and part load coal fire and stable n-1 Operation, cope with expected changing Fuel Properties (e.g. Xylite, LHV), increase of availability, change of fuel distribution in furnace and finally NOx emission below 200 mg/Nm³ @ 6% O2, dry STP while having CO emissions below 200
mg/Nm³ @ 6% O2, dry STP. In order to reach the targets the following measures were implemented: Improve mill capacity, improve grinding fineness, advanced unit capability and availability, optimized burner performance and beneficial dust distribution. The takeover certificate could be issued after having conducted a successful NOx performance test in October 2015. Besides the very efforts made to overcome the obstacles of this especially long lasting rehabilitation project jointly with EPS and especially in valuable cooperation with and support by TENT A staff, this report also emphasizes how the rehabilitation measures were supported by numerical calculation methods regarding the design of the mills upgrade/conversion, the measures undertaken for improving dust distribution and the layout for installations comprising a grit recirculation line.
Paolo Schmidt-Holzmann (Steinmueller Engineering GmbH)
Abstrakt
Steinmüller Engineering was contracted by ESKOM to improve the firing system at Camden Power Station. Camden PS is a coal fired plant consisting of eight 200 MWe units. The plant was originally designed for a service life of 40 years and was commissioned during the period 1966-69. Due to surplus capacity the plant was shut down and preserved during the period 1988-90. Due to increasing power demand it was decided to reactivate the plant. First unit was re-commissioned and synchronized in 2005, the return to service process was finalised in 2010. Camden boilers are of front wall fired type, with each unit equipped with 20 burners organized in five rows. The burners belonging to one row are installed in a common windbox. The motivation behind this project was mainly driven by improvement of the reliability of the boiler. The currently installed combustion system caused severe problems during operation leading to unplanned boiler outages, with burners as the main source of problems. To cope with the mentioned challenges the existing burners were replaced with modern Low-NOX burners, which are characterised by very precise ignition and flame control. Simultaneously the new burners reduced the NOX emissions. Steinmüller Engineering implemented a solution with minimal impact on the existing system, in terms of scope of required modifications. The engineering phase to customize the design to meet the specific requirements of the boiler is completed. In 2015, the manufacturing and installation, executed by local companies, is completed for the first two units. The other units follow subsequently in the next years. Installed Low-NOX burners are of Steinmüller Engineering’s latest generation bituminous coal burners.
Mr. Pietro Marioni (VICODA GmbH)
Dr. Eng. Slobodan Djekic (Inter Kontakt - Energo d.o.o)
Abstrakt
Paper is dedicate to present main element of theory related to the vibration problems, their evaluation, approach as well as some examples from practice where technical solutions of Vicoda GmbH have secured further safe and reliable operation of power plants.
Vibrations often leads to a serious risk of structural damage, which would affect the service life of power plants installations. In fact, vibrations may affect different sections of a plant due to several reasons:
• piping systems, due to unsteady-state flow, turbulent flow, liquid hammers, valves switching and connected heavy equipment
• rotating equipment, like turbines, coal mills, fans, compressors, engines or pumps due to their proper functioning (unbalanced rotating or shifting masses)
• structural parts like chimneys or buildings, due to connected piping systems, heavy machinery or other operational causes
In addition, heavy local traffic, wind and earthquakes are further excitation sources. Depending on the geographical area, they may strongly increase the dynamic effect and the corresponding risk.
Disregarding dynamic problems may lead to structural damages, which affects to the production efficiency, maintenance cost and finally the health and safety measures. For this reasons, in the last decades vibration control has become more and more a strategic and widespread technique in order to reduce this risk. VICODA GmbH provides adequate knowledge and solutions to isolate or damp undesirable vibrations in all industrial fields.
Ivan Božić (University of Belgrade Faculty of Mechanical Engineering)
Miloš Tanasijević (University of Belgrade Faculty of Mining and Geology)
Predrag Mlađenović (Limske Hydropower Plants)
Ljubiša Ljujić (Limske Hydropower Plants)
Stojan Trtović (Limske Hydropower Plants)
Dragan Zorić (Limske Hydropower Plants)
Aleksandar Jakšić (Limske Hydropower Plants)
Darko Bjelić (Limske Hydropower Plants)
Abstrakt
The hydropower plants within the Limske hydropower plants have been in operation for decades, and while anticipating the beginning of their inevitable revitalization and reconstruction it is of great significance to establish the appropriate maintenance in order to prevent unforeseen failure and to extend lifetime of the hydraulic turbines. Although hydropower plants belong to the category of reliable technical systems, their important feature is also reflected in the consequences due to potential failures. For such systems, the risk based maintenance concept is proposed in the maintenance engineering practice. Therefore, in this paper, based on the expert failure analysis of vital components of the existing Francis turbines within the four plants, the risk assessment is performed by the Risk Priority Number (RPN) methodology. For analysis of partial indicators of risk in real conditions, descriptive linguistic variables for the assessment of components were provided in adequate questionnaires by experienced engineers who have been working in maintenance and exploitation in Limske hydropower plants for long. According to the obtained results, the priorities in control checkups of the hydraulic turbine vital components for each analyzed hydropower plants are recommended.
Saša Milanović (University of Belgrade Faculty of Mechanical Engineering)
Ivan Božić (University of Belgrade Faculty of Mechanical Engineering)
Gordana Bakić (University of Belgrade Faculty of Mechanical Engineering)
Abstrakt
In a wide range of operation, it is very difficult or even impossible to avoid the occurrence of cavitation in certain flow passages of hydraulic turbines. The negative effects of cavitation, such as erosion, on the hydraulically designed geometry influence the reduction of the turbine energy performance. In previous decades, numerous researches have been done in order to avoid or reduce these effects, and general tendency was to make certain design changes in the geometry of the flow passages, particularly the runner blades, as well as in the application of different kinds of materials. Continuous improvement in research and testing methods and monitoring cavitation, as well as in new materials and protective coatings for manufacture and reparation of turbines has led to energy indicators improvement and turbine lifetime extension. In this paper, modern methods for hydraulic turbines prevention from cavitation erosion are presented, with particular emphasis on laser peening procedures and specific perforation of runner blades, but also on different ways of the runner aeration.
Miodrag Arsić (Institute for materials testing, Bulevar vojvode Mišića 43, Belgrade)
Srđan Bošnjak (Faculty of Mechanical Engineering, Belgrade University, Kraljice Marije 16, Belgrade)
Vencislav Grabulov (Institute for materials testing, Bulevar vojvode Mišića 43, Belgrade)
Mladen Mladenović (Institute for materials testing, Bulevar vojvode Mišića 43, Belgrade)
Zoran Savić (Institute for materials testing, Bulevar vojvode Mišića 43, Belgrade)
Abstrakt
Technical diagnostics, concerning the turbine and hydromechanical equipment, should rely on certain testing procedures, history of use of turbine and hydromechanical equipment with expert knowledge regarding the structures and operating conditions, as well as on the analysis of results performed by experts with appropriate experience and knowledge in design, exploitation, maintenance, reliability, fracture mechanics etc. Degradation of properties of the material and/or welded joints
at structures and components of turbine and hydro-mechanical equipment is being caused by the simultaneous
influence of a large number of technological, metallurgical, structural and exploitational factors. In this paper some examples where non-destructive tests enabled the determination of causes of degradation of base material or welded joints, as well as identification of elements necessary for expert decisions regarding the methodology that is supposed to be used for the rehabilitation of components of turbine and hydro-mechanical equipment (repair welding, repair of damaged surfaces by cold metallization, use of new technologies and materials, corrections of existing structural solutions) in order to improve their technical characteristics and extend the service life of the hydroelectric generating set are presented.
Dane Džepčeski (Elektrotehnički institut „Nikola Tesla“ University of Belgrade, Belgrade, Republic of Serbia)
Vladimir Stanojčić (Elektrotehnički institut „Nikola Tesla“ University of Belgrade, Belgrade, Republic of Serbia)
Nemanja Milojčić (Elektrotehnički institut „Nikola Tesla“ University of Belgrade, Belgrade, Republic of Serbia)
Marko Mijić (ELNOS BL, Banja Luka, Republic of Srpska, BiH)
Mladenko Đaković (ZP „Hidroelektrane na Vrbasu“ A. D. Mrkonjić Grad, Republic of Srpska, BiH)
Nedeljko Todić (ZP „Hidroelektrane na Vrbasu“ A. D. Mrkonjić Grad, Republic of Srpska, BiH)
Anđelko Grahovac (ZP „Hidroelektrane na Vrbasu“ A. D. Mrkonjić Grad, Republic of Srpska, BiH)
Abstrakt
Small hydro power plant (SHPP) which is placed in facility of HPP “Bočac“ is built with idea of its possible multipurpose use. One of SHPP way of usage, which is envisaged by main project, is work of SHPP as auxiliary power supply generator set of HPP “Bočac“. Before of SHPP technical acceptance and prior of hydro unit commissioning, necessary adjustments and tests of unit were made.
In this paper, results of unit testing which are primarily related to unit work as auxiliary power supply generator set, when unit works in island mode, are shown. This mode of unit operation is, regarding to unit equipment and also consumers, most difficult and such as most interested for detail analysis. Test results of step loading and unloading of unit with switching on and off of different parts of isolated 35kV grid, different devices in internal 0,4kV network and 0,4kV network of auxiliary facilities of HPP “Bočac”, are shown.
Radomir Stamatović (Institute Mihailo Pupin - Automatika, Belgrade, Serbia)
Aleksandar Car (Institute Mihailo Pupin - Automatika, Belgrade, Serbia)
Nikola Stojaković (Institute Mihailo Pupin - Automatika, Belgrade, Serbia)
Ivana Kršenković (Institute Mihailo Pupin - Automatika, Belgrade, Serbia)
Abstrakt
The paper describes calculations of the theoretical solar power and energy, for the appropriate geographic location, in different time intervals. For the theoretical solar power and energy calculations are used well-known expressions and rules from astronomy and physics of solar radiation. The values like overall performance of energy production, losses in production and solar resources, are calculated from SCADA system archived data. SCADA reporting subsystem, also, shows influences of the ambiental temperature, temperature of panels, as well as wind speed, on production of the rooftop photovoltaic power plant. Recommended parameters in standardized reports are reference yield, total yield of the PV power plant, performance ratio. In addition, in the paper are analyzed those parameters against theoretical data. Generating reports, tables and graphs were implemented by SCADA report system and web applications in LAMP technology.
Dr.-Ing Thomas Krause, Head of Firing Components (MITSUBISHI HITACHI POWER SYSTEMS EUROPE GmbH, Schifferstraße 80, 47059 Duisburg, Germany)
Falk Hoffmeister, Head of Firing Systems (MITSUBISHI HITACHI POWER SYSTEMS EUROPE GmbH, Schifferstraße 80, 47059 Duisburg, Germany)
Abstrakt
Units’ no. 3, 4 and 5 at TPP Nikola Tesla A have a nominal Power output of 308 MW. Each unit is equipped with 6 DGS® 100 mills. Referred to the mill load, which is necessary to prepare the fuel for the firing process, the coal quality has become worse during the last years. Today the coal is harder to grind, as it has a high content of wooden parts (Xylite) and sometimes there are quite big lumps inside the raw coal. Caused by this worse coal quality the output of the mills was reduced from 97t/h down to about 85t/h, which was not sufficient to reach 100% boiler load with 5 (n-1) mills in operation.
Already in the year 2006 two DGS® 100 mills on unit A3 were successfully upgraded to verify the possibility to increase the mill load despite of the changed coal quality back to 100 t/h per mill.
Looking forward to a Low NOx Rehabilitation it was decided to increase the mill throughput further to have the potential for this NOx reduction as well as for an increase of the boiler load.
In 2010 the remaining four mills on unit A3 were upgraded. The acceptance tests verified an increased mill throughput greater than 110t/h, combined with an improved grinding fineness. With the upgraded mills, 100% boiler load can be operated with 5 mills (n-1) or if necessary even with 4 mills (n-2). The upgrade of the six mills DGS® 100 on unit 4 was done in 2011 with comparable good results.
In 2012 the upgrade of the six mills DGS® 100 on unit 5 was done in combination with a Low NOx Rehabilitation. With the upgraded mills on unit 5 the requirements of Low NOx firing system with improved grinding fineness and beneficial coal dust distribution could be fulfilled.
The presentation will inform about the mill modifications that make it possible to upgrade the mills for the boiler load increase and to lay the foundation for the Low NOx Rehabilitation.
Milan V. Petrović (University of Belgrade-Faculty of Mechanical Engineering, Belgrade)
Srđan Milić (University of Belgrade-Faculty of Mechanical Engineering, Belgrade)
Milan Banjac (University of Belgrade-Faculty of Mechanical Engineering, Belgrade)
Srećko Nedeljković (University of Belgrade-Faculty of Mechanical Engineering, Belgrade)
Dejan Đukanović (University of Belgrade-Faculty of Mechanical Engineering, Belgrade)
Miloš Ranković (University of Belgrade-Faculty of Mechanical Engineering, Belgrade)
Marija Stevanović (Electric Power Industry of Serbia, Thermal power plant Morava, Svilajnac)
Gordana Novaković (Electric Power Industry of Serbia, Thermal power plant Morava, Svilajnac)
Abstrakt
Thermal Power Plant Morava, Svilajnac is in operation since 1969 and by 2015 had more than 220,000 operating hours. In 2015 a major overhaul of the steam turbine plant was carried out during which the existing IP turbine was replaced by a new modern machine. Upon completion of the overhaul, a comprehensive testing of the steam turbine plant was conducted. The aim of this test was to determine the reference state of the plant and its the most important components and to obtain reference data for future operation and maintenance of the plant. The paper presents the measuring technique, method of measurement data evaluation and the main results of the test. The overall heat rate and the theramal efficiency of the steam turbine plant, as well as, operating characteriatics of all its components were determined. The mass and energy balances for several operating loads were made. Based on the obtined results, the impact of deviation of individual parameters and deviation in operation of components on electrical output and heat rate was calculated. The guidelines for operation of thermal power plant were given.
