The weekly cost-optimal generation of electric power in a hydrothermal generation system is modeled as a multistage mixed-integer stochastic program. The model incorporates uncertainties of electrical load forecasts, of inflows to pumped storage hydro plants and of fuel or electricity prices. For its solution a stochastic Lagrangian relaxation scheme is designed by assigning (stochastic) multip...

Hydro generation scheduling is a nonlinear programming problem. This paper describes the hydro generation scheduling problem constraints. The optimal hydro scheduling problem is formulated as a large scale linear programming algorithm and is solved using a commercially available linear programming package. The selected objective function requires minimization of demand and generation of a hydro...

Variable frequency transformer (VFT), introduced recently is a flexible asynchronous ac link which is used in power transferal process between asynchronous power system grids. VFT was first installed at Langlois substation, which interconnects the Hydro-Québec (Canada) and New York (USA) systems. The torque of the rotary transformer is externally altered in order to control the direction and ma...

We analyze the flux power spectrum and its covariance using simulated Lyα forests. We find that pseudo-hydro techniques are good approximations of hydrodynamical simulations at high redshift. However, the pseudo-hydro techniques fail at low redshift because they are insufficient for characterizing some components of the low-redshift intergalactic medium, notably the warm-hot intergalactic mediu...

We analyze the flux power spectrum and its covariance using simulated Lyα forests. We find that pseudo-hydro techniques are good approximations of hydrodynamical simulations at high redshift. However, the pseudo-hydro techniques fail at low redshift because they are insufficient for characterizing some components of the low-redshift intergalactic medium, notably the warm-hot intergalactic mediu...

Most of the methods developed for hydrothermal power system planning are based on scenario-based stochastic programming and therefore represent the stochastic hydro variable (water inflows) as a finite set of hydrological scenarios. As the level of detail in the models grows and the associated optimization problems become more complex, the need to reduce the number of scenarios without distorti...

The aim of this paper is to assess the capability of the emerging synchronized phasor measurement technology in improving the overall stability of the Hydro-Quebec’s transmission system through supplementary modulation of voltage regulators. Following a thorough singular value and eigenvalue analysis of the system dynamic interactions, five control sites consisting of four generators and one sy...

The verification of existing plans for network restoration after blackouts in European electrical energy systems becomes more and more important with the ongoing deregulation process. For this verification high quality computer models of the electrical system are necessary which are able to generate exact results for all possible restoration scenarios. The most important elements of these model...