Abstract
The restructuring of power systems has often originated the organization of power system operation planning in a set of chronological sequence of activities that are reasonably decoupled. This means that the Market Operator purely economic schedule together with bilateral contracts is conveyed to the System Operator to be validated from a technical point of view. The System Operator also has to schedule reactive power but some of its reactive power requirements may be unfeasible given the previous active power schedules and the alternator capability diagram. Apart from this aspect, active and reactive powers are coupled in determining the eventual violation of branch thermal limits and reactive power has a well-known local nature. While recognizing the Coupling between active and reactive powers, the models presented in this paper admit that the Market Operator schedule may have to be altered either because there are branch limit or nodal voltage violations or because the System Operator requires a reactive output that can not be provided Clue to the previous active schedule. The changes on the initial schedule are determined by solving an optimization problem that uses adjustment generator or demand bids. Apart from that, we adopted a symmetric fuzzy programming approach recognizing that some constraints have a soft nature, namely the ones related with voltage and branch flow limits. To solve the resulting non-linear problem we used Sequential Linear Programming, SLP. At its final iteration this problem also Outputs active and reactive nodal marginal prices useful to build more effective tariff systems. The paper includes a case study based on the IEEE 24 bus test system.

Abstract
This paper addresses the generation expansion-planning problem describing a model that generation companies can use to get insight to this problem and to more completely study and characterize different investment decisions. In the last 20 years, the generation activity evolved from a situation in which it was part of vertical companies to unbundled market agents that face a much more risky and uncertain environment. This explains the need to develop this kind of simulation tools to help them building their investment plans as well as analyzing the impact of possible decisions of other players. The simulation model considers a number of possible generation technologies and aims at characterizing the corresponding investment plans from an economic point of view having in mind that market prices, the demand growth, investment and operation costs, as well as other factors, are affected by uncertainties. These uncertainties are modeled by pdf functions and the solution approach uses a Monte Carlo Simulation to sample particular values used to analyse the different investment alternatives from an economic point of view. Finally, the paper presents results from a Case Study illustrating the use of this approach.

Abstract
This paper presents an integrated model to deal with complex bids and network security constraints in electricity markets. Apart from purely economic aspects, power systems operation is also driven by technical issues that quite often turn unfeasible purely economic schedules. This is the case of up and down ramps and minimum technical limits of generators, nodal voltage ranges and branch flow limits. The activities of the Market and System Operators are quite often organized in terms of a sequential set of actions that may not guarantee identifying the best global solution. This suggests addressing the problem in a more integrated way and adopting a well known optimization technique, as Simulated Annealing. This paper describes the mathematical formulation of the problem, the adopted solution algorithm and details a case study based on the IEEE 24 bus/38 branch system.

Abstract
Concepts of MicroGrids are proposed to address primarily various issues related to integration of small scale renewables and increased demand of reliable electricity supply. With an active management control approach and ability to operate in islanding mode, a cluster of micro generators, electricity storage and electrical loads can be operated within the MicroGrids framework to provide higher supply reliability to highly value customers. Solutions are required not only to make these concepts technologically feasible and safe to operate but also to be commercially viable and attractive, economically efficient and supported by electricity regulations. This paper summarises the results of investigations on various economic, regulatory and commercial issues faced by the development of MicroGrids in MICROGRIDS project. The potential economic benefits and contributions to environment from applications of MicroGrid technologies are also presented and described in this paper.

Abstract
This paper presents a mathematical formulation for the active/reactive dispatch in electricity markets, recognizing that the typical sequential activities organized in terms of pool markets and the dispatch of ancillary services may lead to economic inefficiencies or technical difficulties. The developed model admits that it is known the purely economic pool dispatch and then it aims at dispatching reactive resources considering voltage and branch limit constraints and constraints reflecting the alternator capability curve. We also admitted that some constraints have a soft nature and used a symmetrical fuzzy decision formulation to model this aspect within an SLP based algorithm. Finally, the paper includes a case study based on the IEEE 24 bus/38 branch system to illustrate the results obtained with the developed approach.

Abstract
This paper presents an approach to reliability evaluation of generation/transmission power systems using the Monte Carlo simulation method. In this approach uncertainties are represented using two different frameworks. For one side, probability concepts are used to represent the failure-repair cycle of system components. Loads are represented through classified load diagrams in which each time step corresponds to a fuzzy number. This simulation method allows the user to obtain estimates of the expected exposure and robustness indices and of the Power Not Supplied membership function.