Andrzej ZIĘBIK, Paweł GŁADYSZ
System analysis of an oxy-fuel combustion power plant integrated with CO2 capture
Oxy-fuel combustion technology belongs to one of the most promising solutions of CO2 capture systems. Integration of a power plant with air separation and CO2 capture and compression units makes a power system more complex that is why the right approach to the research is a system analysis. Described are mathematical models of direct and cumulative energy consumption balances and a model of a thermoecological analysis based on the input-output analysis. Presented are results of a multi-alternative system analysis of an oxy-fuel combustion integrated power plant concerning, among the others, an impact of various factors like oxygen purity, use of waste energy and replacing the cryogenic air separation with a membrane installation on energy rates. The reduction of an integrated power plant energy efficiency compared to the basic system equals about 10,5 p.p. (percentage point). Recovery of waste heat from interstage cooling of air separation and CO2 compressors increases this efficiency by 0,17 p.p. But a significant improvement, by about 2,6 p.p., could be reached by replacing the presently existing cryogenic air separation unit with a future-oriented membrane one.
Keywords: coal-fired power plants, oxy-fuel combustion, CO2 capture
Distributed PV sources – a potential to shape the profile of KSE (national power system) during a summer peak period
Presented are possibilities to change source structures in the KSE and increase participation of RES. Expected is that over the next few years summer peak demands will steadily and quickly grow and with summer high temperatures and low water levels the traditional coal-fired power stations will still be exposed to risk of efficiency reduction and probability of major failure caused by generation units difficult working conditions. Considerable support for traditional power industry can be the one basing on renewable resources but for this a sustainable RES development is needed ensuring their diversification. At present, among various renewable energy resources, the best developed one in Poland is the wind power industry but during summer time when the weather is nice and stable that kind of generation is on a relatively low level. In these periods the distributed PV resources work very well and they are able to supplement peak power shortfalls by either injecting energy into networks (PV farms, surplus power produced by prosumers) or reduction of power demand from the side of end users-prosumers in microscale (individual housing) and macroscale (enterprises, office buildings, public institutions etc.). Distributed prosumer installations also relieve a transmission system as the electric power generation takes place directly in power intake points or in their surroundings.
Keywords: summer power shortages in KSE, changes in power sources structure, increasing of RES participation
Zbigniew USAREK, Bolesław AUGUSTYNIAK, Marek CHMIELEWSKI
Application of FEM (Finite Element Method) for assessment of a probe velocity impact on the MFL (Magnetic Flux Leakage) signal from a surface defect
Suggested is an interpretation of an effect of the increase in the value of the measured diffused field strength as a function of a magnetizing system speed. Simulation results obtained by FEM method allow to assume that the increase is a consequence of a specific „pushing out” of a magnetic flux onto the plate surface by eddy currents. The conducted numerical analysis proved to be very helpful for interpretation of experimentally observed in MFL signal strength changes following the velocity increase. This indicates considerable usability of FEM modeling as a tool supporting research on physical bases of non-destructive magnetic methods. And though the MFL signal shape and amplitude dependency of a magnetizing probe velocity impedes the quantity assessment of defect dimensions in in situ research, the increase of MFL signal amplitude as velocity function is a positive phenomenon. Still it should be noted that this kind of increase tendency is characteristic for near-surface defects placed on the probe side. In case of inner defects and the near-surface ones placed on the opposite side to the probe, the MFL signal dependency on velocity can be of other character and, in particular, the signal can be declining. This is a very important technical problem that makes it impossible to process the MFL signal to quasi-static form (corresponding the zero velocity) in an unambiguous way with no information concerning defect location deep in the investigated surface. But, in the authors’ opinion, the problem can be solved thank to simultaneous application of flaw detection methods supporting MFL measurements by the assessment of defect location relative to the scanned surface.
Keywords: power installations, non-destructive measurements, Finite Element Method
Resistance of composite insulators to mechanical hazards
Growing application of composite insulators needs improvement of not only the criteria of their technical acceptance but also verification and expanding current investigations. As a proposal of new investigations described in this article is going into direction of taking into consideration the resistance of composite insulators to cyclic loading. The necessity of conducting such investigations was taken into account in the new PSE S.A. technical specification „Hang-type composite insulators for a 400 kV network” (July, 2015). Further research should include new phenomena and conform to increasingly stringent quality criteria, meeting which can considerably influence durability of such insulators.
Keywords: 400 kV transmission networks, composite insulators, insulator endurance tests
Modeling of ground faults in overhead-cable HV power lines
Presented are selected problems referring to modeling of transient electromagnetic states connected with short-circuits and especially their ground fault types in overhead-cable HV power lines. The model of an overhead and cable line includes dependency of the line substitute parameters on frequency. The obtained results of simulation studies for a model of a 110 kV network with an overhead-cable line can be used to investigate decision criteria of automatic power system protection equipment e.g. distance line protection against results of fault interferences.
Keywords: modeling of electromagnetic transient states, ground faults, cable and overhead-cable HV lines
Effective energy cooperation and cultural differences between Poland and India
Discussed are cultural diferences between the two nations. They are, amongst the others, a complete different perception of business relations, aversion to take decisions and a very different approach to timeliness, duration and sustainability of contacts. In both countries we deal with bureaucracy but in India the bureaucratic apparatus is much more extensive. Like many things concerning the Indian nation as the whole, the hierarchy system has been implemented and firmly rooted as an obligatory one in working places. India is also a country of an „outer” culture by which the behaviour is aligned with requirements of the actual situation. There are various reasons for it but one must remember that in India it was rather a man that tried to adjust himself to the nature or circumstances instead of trying to change the surrounding conditions. Indian culture is focused on a client and relations while Western cultures are rather aimed at economy. This strong hierarchy system caused creation of the „nodding in agreement culture” and a complete lack of objections so a man cannot be surprised by sudden changes in relations or even termination of provisional agreements. But energy cooperation with this country is a chance for Poland, and Poland is still the most similar to India than any other European country.
Keywords: energy cooperation with India, cultural similarities and differences