SELECTED PROBLEMS OF TURBOGENERATORS PROTECTION

Anton Beláň - Žaneta Eleschová - František Janíček - Ferdinand Varga

   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 [1], [2]. 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 [3]. The frequency or angular velocity is one of important parameters of operation of the PS [4]. 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.

1. Chladný, V. - Hudák. D.: Electric Protections in Power Systems, Bratislava, Alfa, 1977
2. Janíček, F. - Chladný, V. - Beláň, A. and Eleschová, Z.: "Digital Protections of Electric Machines", Košice, FEI TU 2000
3. Chladný, V.: "Digital Measurement Method of Local Frequency in Power System", Proceeding of International Science Conference Elektroenergetika 1997, FEI VŠB-TU Ostrava, 1997
4. Trojánek, Z. - Hajek, J. and Kvasnica, P.:Transient Phenomena in Power System, SNTL, Praha 1987, p. 310

Keywords: turbogenerator, excitation, turbine, frequency, static and dynamic stability of PS

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