The revitalization of hydro-aggregates should be performed before the life-time expiry of most their parts. But, as in our practice aggregates have been under exploitation much longer then theoretical life-time advices (40, even 50 years), there is a need to estimate the equipment's condition through more sophisticated monitoring, providing the maximum level of safety and availability with minimum investment expenses, before the revitalization finally takes place. That estimation is based on appropriating calculations and measurements needed to take the competent decision. Results of that analysis can be also useful for estimation of the aggregate's power and parameters after the revitalization. In this paper the results of appropriate calculations and measurements for the Hydropower station HE Zvornik are given. .

Summary In this paper, a synchronous generator excitation controller based on a novel feedforward control action is proposed. The main purpose of the new feedforward action is to enable a more robust excitation of the synchronous generator operating in varying operating conditions when connected to a power grid, for any superimposed stator voltage controller. Namely, the dynamic performance of the proposed controller is compared with a conventional proportional‐integral (PI) controller, and with the PI controller combined with a feedforward action based on the direct component of the stator current. It is analytically shown that the novel controller improves the robustness when compared to 2 aforementioned solutions. Also, by simulation and experimental tests, it is shown that for the loaded synchronous generator, the novel controller, which is designed to have a similar response speed in open circuit as conventional controllers, exhibits up to 2 times faster dynamic performance.

Kratak sadržaj: U ovom radu dat je prikaz procedure za određivanje vrednosti parametara regulatora pobude na osnovu step promene reference u praznom hodu. Regulator pobude sastoji se od PID regulatora i tiristorskog mosta kao izvršnog organa. U sistemu pobude zatvorene su dve povratne sprege: unutrašnja povratna sprega po struji pobude i spoljašnja povratna sprega po struji pobude u slučaju strujnog regulatora odnosno povratna sprega po naponu statora u slučaju naponskog regulatora. Procedura za određivanje parametara opisuje određivanje ekvivalentnog pojačanja regulatora i tiristorskog mosta. U radu su određeni parametri regulatora na osnovu merenja i snimaka sa agregata A5 u TE ''Kolubara A''.

Kratak sadržaj: U radu su prikazani rezultati garancijskih ispitivanja sistema pobude agregata A4 u HE "Đerdap 1". Sistem pobude je pušten u rad u okviru revitalizacije agregata 2013. godine, dok su garancijska ispitivanja obavljena tokom 2014. godine. Cilj ovih ispitivanja je bio dokazivanje garantovanih parametara novougrađenog sistema pobude. Za potrebe ispitivanja je korišćena merna oprema koja u svemu odgovara zahtevima navedenim u tehničkom standardu GOST 11828-66 i koja je prethodno etalonirana.

Kratak sadržaj: U radu su prikazani ekvivalentni modeli automatske i ručne regulacije sistema pobude agregata A1 u HE "Pirot" i date su vrednosti svih parametara sistema pobude. Na osnovu eksperimentalno dobijenih snimaka odziva na odskočne promene reference regulatora sistema pobude identifikovani su parametri ekvivalentnog modela automatske regulacije i upoređeni su sa vrednostima parametara koje su podešene na samom regulatoru. Eksperimentalno su određene vrednosti statizma po reaktivnoj snazi na generatorskim i mrežnim sabirnicama agregata.