Presented article deals with the determination of hydrogenerator electromagnetic parameters from the SSFR test. A method utilized to prepare the results is finite element method based on the module of Steady State AC Magnetic 2D application. Obtained reactances could be determined after an application of own made program used to fit the curves (magnitude and phase characteristic of operator transmittances) to the data coming from the simulation in order to designate the time constants. An impact of saturation effect in stator and rotor steels was researched on obtained reactances in different working states of synchronous machine.
Słowa kluczowe: hydrogenerator, finite element method, electromagnetic parameters, Standstill Frequency Response test.
Prezentowany artykuł przedstawia symulacyjną metodę wyznaczania parametrów elektromagnetycznych hydrogeneratora z testu SSFR (Standstill Frequency Response). Zastosowana metoda obliczeń bazuje na rozkładzie pól sinusoidalnie zmiennych o zadanej zmiennej częstotliwości. Reaktancje hydrogeneratora zostały wyznaczone ze stałych czasowych za pomocą opracowanego programu. Program ten dopasowuje charakterystyki amplitudowe i fazowe do wartości otrzymanych z symulacji. Zbadano wpływ nasycenia obwodu magnetycznego na reaktancje odzwierciedlające zachowanie maszyny w różnych stanach pracy.
Keywords: hydrogenerator, metoda elementów skończonych, parametry elektromagnetyczne, SSFR test
The electromagnetic parameters of a synchronous machine are most often determined during running tests from no-load and three phase short circuit tests . These tests are carried out most often at the manufacturer of electrical machines at the test station, which is equipped with a properly selected drive and a constant voltage source. Typically, such equipment is sufficient to test machines with several poles and rated power not exceeding approximately 10 MVA. The problem is encountered when the power is higher and the number of pole pairs exceeds 20-30. Then the measurement of such a machine is difficult due to its dimensions and the lack of a suitable source of DC voltage. The SSFR (Standstill Frequency Response Test) measuring method , which does not require a separate source of direct voltage, can be opposed to these difficulties and can be carried out on the site, eg after being built in a power plant. This method consists in forcing the voltage at a given frequency, at the right position of the rotor (direct and quadrature axis) and with the open or closed excitation circuit. Initially, it was only used to study synchronous machines with a cylindrical rotor (eg turbogenerators), but with its refinement and modification, it was also used in machines with rotor of salient pole [3-6]. Standstill Frequency Response test is used to determine the electromagnetic parameters such as the reactances and the time constants which can be utilized to compute the resistances and the inductances needed to prepare an equivalent machine circuit . In this way new-created equivalent hydrogenerator model allows to predict the dynamic behaviour of the machine during the abnormal operating states. SSFR test is relatively cheaper than the preparation of no-load and sudden short circuit tests during the running test. The price of the standard test is determined by the auxiliary instruments included during the tests such as the oil [...]
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