Characterization of surge superposition following 2-stage load rejection in hydroelectric power plant

2016 ◽  
Vol 43 (9) ◽  
pp. 844-850 ◽  
Author(s):  
Sheng Chen ◽  
Jian Zhang ◽  
Xichen Wang

When calculating the maximum upsurge in surge tank due to load rejection in a hydroelectric power plant, it has been natural and customary to believe that the maximum surge amplitude occurs in simultaneous load rejection of all units at 100% load. As 2-stage load rejection (2-stage LR), involving a step-wise reduction in load, is not considered since it is assumed to produce less severe surge conditions. This study formulates the surge superposition associated with 2-stage LR and shows, surprisingly but significantly, that such 2-stage LR sometimes produces more severe surge conditions than simultaneous and complete load rejection (SCLR). The results indicate that this unexpected phenomenon is ascribable to the resistant effect of throttled surge tank, whose increase will lead to a greater difference in the maximum upsurges between 2-stage LR and SCLR conditions. Different time intervals during 2-stage LR correspond to different maximum upsurges. The analytical formula predicting the worst interval time is derived exactly and verified with two numerical cases.

Author(s):  
Iva´n F. Galindo-Garci´a ◽  
Antonio Tavira-Mondrago´n ◽  
Sau´l Rodri´guez-Lozano

A simulation model of the hydraulic system of a hydroelectric power plant is developed and implemented in a real time simulator. The main purpose of the simulator is to test the performance of actual governor control systems using hardware-in-the-loop techniques, in which the actual governor control system is connected to a real time simulator instead of being connected to real equipment. This paper focuses on the modeling of the hydraulic system to be implemented in the simulator. The model consists of an unrestricted reservoir, conduits to transport water, and a turbine to convert the potential energy of the fluid into mechanical power. A nonlinear mathematical model for a non-elastic water column is implemented. Effects due to a surge tank and to various turbines connected to a common tunnel are included in the model by considering head and flow variations at the junction of the common tunnel and the individual penstocks. The model is evaluated by comparing results from simulations with field tests from a four-unit hydroelectric power plant (55 MW per unit). Comparisons show that the model reproduces the general behavior of the field tests. However some deviations are observed during the transient response, in particular the simulation results appear to respond faster than field data.


2018 ◽  
Vol 8 (2) ◽  
pp. 85
Author(s):  
Silvanete S. da Silva

The erosive processes generated at the reservoir banks affect the quantity and the water supply, causing serious environmental and economic consequences. The objective of this study was to define the erosive laminar process in the surroundings of the reservoir of the Hydroelectric Power Plant. To perform the evaluation in sixteen areas, Echanced Thematic Mapper Plus images were used from Ladsat 7 satellite, RGB color composition and 543 bands, with nine classes of use and occupation of the areas, as well as the methodology with erosion pins. The pedological survey revealed a variation in the taxonomic classes, such as: Eutrophic Regolithic Neosol (area 1); Eutrophic Littoral Neosol (areas 2, 3, 4, 12 and 13); Optical Quartzene Neosol (areas 4, 6, 7, 8, 9, 10, 11 and 16); Luvissolo Crômico Órtico (area 5); And Eutrophic Haphol Plantain (area 15); The physical characterization of the soils and the soil loss of the marginal debulking (ranging from the very low to severe level) studied were susceptible to erosive processes. Soil loss in the studied areas varied from 85.00 to 205.20 kg ha-1ano-1. 


2002 ◽  
Vol 122 (6) ◽  
pp. 989-994
Author(s):  
Shinichiro Endo ◽  
Masami Konishi ◽  
Hirosuke Imabayashi ◽  
Hayami Sugiyama

Author(s):  
Michal Kuchar ◽  
Adam Peichl ◽  
Milan Kucera ◽  
Jaromir Fiser ◽  
Pavel Kulik ◽  
...  

2014 ◽  
Vol 36 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Maciej Korczyński ◽  
Ewa Krasicka-Korczyńska

Abstract Cypripedium calceolus is considered an endangered species in the territory of Poland. Population of this rare species, situated at Lake Kwiecko (Western Pomerania), was regularly monitored in the years 1986-2013. The studied population has been under the permanent influence of the nearby hydroelectric power plant for almost 45 years. The field observations showed that the power plant had no negative impact on the condition of Cypripedium calceolus population. An indication of its good condition was, among others, an increase in the size - from 150 to 350 specimens within the study period.


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