Any O P F tool used in on-line minimum loss calculation requires a n accurate representation of t h e external or unobservable parts of t h e network. This paper proposes an optimization model of both internal and external network represented explicitly. Although requiring only external network d a t a , any available information about t h e external s t a t e may be used t o improve its response. A general methodology for t h e performance analysis of Equivalent OPF models is also proposed. On one level, t h e robustness of equivalent models for t h e production of accurate control actions in t h e internal system is analyzed. Accurate control actions a r e those t h a t a r e as close as possible to t h e controls obtained through a hypothetical OPF solution of t h e complete system. On a second level, t h e capacity t o react accurately, when such control actions a r e set in t h e internal system, is investigated. T h e proposed model and t h e Extended Ward equivalent have been tested through t h e presented methodology. T h e proposed model has been capable t o take into account t h e information related t o t h e optimization "status" (under optimization or not) of external system. This is an important information since it affects considerably t h e internal control action calculation. This information can not be incorporated in t h e reduced equivalent models. Computational test results with t h e Brazilian South-Southeast 810 bus real system a r e presented.
In this paper, we propose a primal-dual interior/exterior point method that uses the modified logarithmic barrier function together with a quadratic test strategy and new search direction procedures for solving the reactive optimal power flow problem. The quadratic test is proposed as an alternative strategy for the Cholesky procedure for calculating the positivity of the Hessian matrix of the problem. The new search directions investigated in the paper are determined by combining the search directions calculated in the predictor and corrector steps, and also by using information associated with the complementarity conditions. The method is implemented in Matlab and applied to solving the reactive optimal power flow problem for 9 and 39 bus systems, as well as for the IEEE 14, 30, 57 and 118 test systems. The results reinforce the efficiency of the method proposed for solving the problem.
Network-constrained market clearing procedures in pool-based electricity markets of hydropower systems have traditionally neglected the constraints associated with physical and operating aspects of hydroelectric generation (hydraulic constraints). Such constraints are generally taken into account by means of expost procedures, which may lead to suboptimal results regarding social welfare function. This paper proposes a network-constrained auction model for hydrothermal systems that represents the hydraulic constraints in detail. The objectives of the paper are twofold: the analysis of the impact of hydraulic constraints on market clearing prices and on generation/consumption scheduling and the analysis of the influence of strategic offering of hydro plants in the operation of a hydraulic cascade. As some of the hydraulic constraints are nonlinear and intertemporal, linearization techniques are applied, resulting in a mixed-integer linear programming problem.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.