Modeling the incremental cost and water conversion functions for hydro-thermal coordination studies
- Dept. of Electrical Engineering, Technical Univ. of Nova Scotia, Halifax, Nova Scotia (CA)
The solution of an optimization problem using variational means relies on Lagrange multiplier functions, called the adjoint variables to augment the physical constraints to the cost function. The multipliers usually have en economic interpretation, and in the optimal economic operation of an electric power system, one set of multipliers signifies the incremental cost of power delivered at a bus, and the other set relates to the water worth at a given reservoir. The solution of the optimization problem involves iterative techniques to obtain the optimal strategy in terms of power generations and water releases, as well as the adjoint variables. Good initial estimates are of paramount importance to a successful implementation of any iteration scheme specially those that are Newton based. There is an observed pattern of dependence of the adjoint variables and the system state as described by power demands and water availability. Finding such relationships is useful for generation planning activities as well as in providing initial guesses in the numerical solution of the problem. This paper proposes statistical models for predicting the incremental cost function {lambda} and the water conversion factor {nu} usually encountered in the hydro-thermal power system optimization problem. The method treats the active power demand and the volume of water available as the independent variables. The Least squares and the iteratively reweighted Least squares procedures are used to estimate model parameters. The approach treats the power system as a variable head hydro-thermal system, Kron's loss formula is used to characterize the system performance and losses. Results for an example using a 4 plant network are presented in order to demonstrate the applicability of this approach.
- OSTI ID:
- 5359098
- Journal Information:
- Electric Machines and Power System; (United States), Vol. 19:3; ISSN 0731-356X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Optimal estimation of piece-wise linear incremental cost curves for EDC
First- and second-order aerodynamic sensitivity derivatives via automatic differentiation with incremental iterative methods