Abstract
One of the main dimension criteria for hydro power plants is the dynamic behavior of the system during large load changes such as full load rejection or full load admittance. This causes huge pressure transients in front of the turbine and surges in the surge shafts. In models for dynamic analyses purposes, the turbine defines the flow in the system, partly by the guide vane opening, and for reaction turbines, partly by the change in rotational speed. High head Francis turbines, and in particular pump turbines, have a significant decrease in flow as the rotational speed increases. For governor stability, this is very convenient, as it gives a natural decrease in hydraulic power when the turbine gains speed. Therefore, this effect is often referred to as ``self governing``. Dealing with pressure transients, however, the self governing causes higher change in flow, and thereby higher retardation forces during a load rejection. Dynamics models of hydro turbines are normally based on the assumption that the performance diagram, often referred to as the Hill diagram, represents the turbine behavior stationary, as well as, in dynamic performance. The main purpose of this study has been to check on this assumption by means of an
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Citation Formats
Nielsen, T K.
Transient characteristics of high-head Francis turbines.
Norway: N. p.,
1990.
Web.
Nielsen, T K.
Transient characteristics of high-head Francis turbines.
Norway.
Nielsen, T K.
1990.
"Transient characteristics of high-head Francis turbines."
Norway.
@misc{etde_10141606,
title = {Transient characteristics of high-head Francis turbines}
author = {Nielsen, T K}
abstractNote = {One of the main dimension criteria for hydro power plants is the dynamic behavior of the system during large load changes such as full load rejection or full load admittance. This causes huge pressure transients in front of the turbine and surges in the surge shafts. In models for dynamic analyses purposes, the turbine defines the flow in the system, partly by the guide vane opening, and for reaction turbines, partly by the change in rotational speed. High head Francis turbines, and in particular pump turbines, have a significant decrease in flow as the rotational speed increases. For governor stability, this is very convenient, as it gives a natural decrease in hydraulic power when the turbine gains speed. Therefore, this effect is often referred to as ``self governing``. Dealing with pressure transients, however, the self governing causes higher change in flow, and thereby higher retardation forces during a load rejection. Dynamics models of hydro turbines are normally based on the assumption that the performance diagram, often referred to as the Hill diagram, represents the turbine behavior stationary, as well as, in dynamic performance. The main purpose of this study has been to check on this assumption by means of an experimental investigation. The experiments show that the dynamic trace, by no means, follows the stationary measured flow characteristics. In order to analyse the results a dynamic simulation model of the laboratory system including the turbine, was developed. The turbine model is based on the one dimensional Euler turbine equation, which basically describes how the turbine behaves at different modes of operation. The author has proven that the reason for the different behavior of the turbine in stationary and dynamic performance is the hydraulic inertia between the defined inlet and outlet of the turbine. 21 refs., 41 figs., 6 tabs.}
place = {Norway}
year = {1990}
month = {Dec}
}
title = {Transient characteristics of high-head Francis turbines}
author = {Nielsen, T K}
abstractNote = {One of the main dimension criteria for hydro power plants is the dynamic behavior of the system during large load changes such as full load rejection or full load admittance. This causes huge pressure transients in front of the turbine and surges in the surge shafts. In models for dynamic analyses purposes, the turbine defines the flow in the system, partly by the guide vane opening, and for reaction turbines, partly by the change in rotational speed. High head Francis turbines, and in particular pump turbines, have a significant decrease in flow as the rotational speed increases. For governor stability, this is very convenient, as it gives a natural decrease in hydraulic power when the turbine gains speed. Therefore, this effect is often referred to as ``self governing``. Dealing with pressure transients, however, the self governing causes higher change in flow, and thereby higher retardation forces during a load rejection. Dynamics models of hydro turbines are normally based on the assumption that the performance diagram, often referred to as the Hill diagram, represents the turbine behavior stationary, as well as, in dynamic performance. The main purpose of this study has been to check on this assumption by means of an experimental investigation. The experiments show that the dynamic trace, by no means, follows the stationary measured flow characteristics. In order to analyse the results a dynamic simulation model of the laboratory system including the turbine, was developed. The turbine model is based on the one dimensional Euler turbine equation, which basically describes how the turbine behaves at different modes of operation. The author has proven that the reason for the different behavior of the turbine in stationary and dynamic performance is the hydraulic inertia between the defined inlet and outlet of the turbine. 21 refs., 41 figs., 6 tabs.}
place = {Norway}
year = {1990}
month = {Dec}
}