Wyniki wyszukiwania - BazTech

1

Monitoring of electric power quality in administrative building

Janíček F., Eleschová Ž., Beláň A.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2006

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Vol. 315, z. 56

165-186

EN

In this paper we deal with a power quality monitoring in a low-voltage electrical circuits in administrative building and with its evolution in accordance with valid technical standard STN EN 50 160. Target of performed measurements was also to measure the current through neutral wire in the view of the triplen harmonic influence. We also realized measurements of potential sources of the higher harmonics in electrical network - transformer, compact fluorescent lamps, and modern appliances with switch-mode power supply concept.

2

Selected problems of turbogenerators ptotection

Belán A., Eleschová Ž.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2005

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Vol. 299, z. 55

42-56

EN

The report brings solutions for selected failure conditions of turbogenerators in power plants. From the point of view of the stability of the power system (PS), the loss of excitation and the following drop-out of these turbogenerators belong to significant failure conditions of turbogenerators of high unit power. The electric protections of turbogenerators play an important role in systematic failure elimination [2], [14]. A complex solution of the protecting system of the most important devices of power plants (turbine, alternator, block transformer) taking into account various operation states faces a problem of dealing with the protection system at forbidden frequencies [9]. The frequency or angular velocity is one of important parameters of operation of the PS [10]. At transition processes the frequency of voltage in PS affects not only the frequency of the fault current but its magnitude as well. An increase in angular velocity has also a negative effect on the static and dynamic stability of PS. The paper presents a calculation of the setting and selectivity of selected turbogenerator protections.

3

Rotor ground fault protection of generator with static excitation system

Eleschová Ž., Belán A.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2005

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Vol. 299, z. 55

81-91

EN

This paper deals with the influence of harmonics produced by the static excitation system of generator on the rotor ground fault protection of synchronous generator. The report brings measured courses of field voltage and current flow through insulation system of field winding during generator failure-free operation. There is analysed potential impact of static excitation system on correct function of rotor ground protection based on AC injection method.

4

Resonance overvoltages in electric power networks

Belán A., Eleschová Ž., Smola M.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2005

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Vol. 299, z. 55

33-39

EN

Resonance exists in circuits composed of inductance and capacitance, possibly resistance. Resonance can cause big overvoltages in power systems. Many resonance circuits, that are present in practice, include induction coils with iron core which that induction is nonlinear. These resonance events are called ferroresonance. In this paper are included measured curves of various variables in case of ferroresonance in auxiliary's circuits of power plant. This paper also includes theoretical analysis of ferroresonance overvoltages on models of electric circuits in EMTP ATP.

5

Power lines protection by digital relays

Smola M., Belán A., Eleschová Ž.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2005

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Vol. 299, z. 55

203-208

EN

This paper shows possible options in protection of power lines by digital relays, that are used in Slovak power system. It shows demands given by STN and possible protection schemes. Electric power lines are still the only media for electric power transportation from power plants to customers and they can be, notwithstanding thoroughgoing operating, liable to various mechanical or electrical failures. Relays can not prevent failures, they just minimize their consequences. This paper shows just a part of power lines protection area, aimed for protection schemes and relays used in Slovak power system. Big systems outages that last year affects power systems in Italy and United States shows, that question of protection coordination and correct choose of protection scheme are significant demands for trouble free operating of power systems.

6

Extending the regulation capacities of the generator in a nuclear power plant

Belán A., Eleschová Ž., Janicek F.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2005

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Vol. 299, z. 55

17-32

7

Expansion of regulation abilities of generator of nuclear power station

Belán A., Eleschová Ž., Janicek F.

Zeszyty Naukowe. Elektryka / Politechnika Opolska

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2004

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Vol. 295, z. 53

69-85

PL

Artykuł analizuje możliwości rozszerzenia zdolności regulacyjnych trzeciego bloku V2 w elektrowni jądrowej Jaslovske Bohunice, poprzez przeprowadzenie symulacji na modelu systemu elektroenergetycznego Republiki Słowacji. Zagadnienie pola niewzbudzenia generatorów i wpływ tego działania na blok transformatora, generator i potrzeby własne bloku.

EN

This article analyses possibilities of expansion of regulation abilities of 3rd block V2 of nuclear power station in Jaslovske Bohunice, by virtue of execution of simulations on model of electric power system of Slovak Republic. This is the question of underexcitation area of generators and impact such operation to block transformer, generator and private consumption of block.