Abstract
Ancillary Services play an important role in power systems since they are crucial to ensure the security and quality of operation. However, this issue is sometimes forgotten and power systems tend to be analysed only from the point of view of electricity markets to schedule active power. In several countries, active and reactive dispatches were decoupled but in fact this causes several inefficiencies and technical difficulties since their schedules is not independent and the two of them determine the operation conditions of power systems. This paper describes an active / reactive dispatch model that retains the competitive aspects currently in force in power systems. It is based on an initial pool dispatch and on adjustment bids used to change generation or load values namely to accommodate losses or to curtail load if that is required to meet operation or technical constraints. This certainly contributes to clarify the roles of the Market and System Operators and to turn the decisions from the System Operator more robust and justifiable from a technical point of view.

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 addresses the short-term allocation of active/reactive power supplies in transmission systems in a market environment. The basic issue addressed by most papers is related to market mechanisms involving active power either in terms of a pool or by bilateral contracts. However, in several countries Volt/Var control started to be considered, at least partially, as a marketable service and so new methodologies are required to support this process. This paper presents an integrated mathematical formulation for the active power dispatch using bids from market agents and inherently taking into account the local nature of Volt/Var control by considering an AC model for the network. The discrete operation of several components as transformer taps and capacitor sections are accurately taken care by using Simulated Annealing. The proposed methodology is applied on the 30-bus IEEE test system highlighting its advantages and demonstrating the feasibility of its use in real systems.

Abstract
This paper describes the design of a Power System Stabilizer synthesized by a static Artificial Neural Network. The patterns used to train the neural network are sets of controller parameters, previously calculated for several system operation points using a pole-shifting method. This neural network stabilizer then operates, in a gain-scheduling scheme, in accordance with the values of active and reactive powers furnished by the generator to the power system, but with soft transition variations of the controller parameters. The trained neural network presents, as its main characteristic, almost uniform values for all the stabilizer parameters when the system synchronous machine is generating reactive power, but these same parameters suffer great variations when the machine is absorbing reactive power. Simulation tests presented show very good performance for the proposed Neural PSS, when compared with a fixed-parameter stabilizer, corroborating the main characteristic of the proposed stabilizer. (C) 2005 Published by Elsevier Ltd.

Abstract
The main objective of this paper is to present the development of microsource modelling and the definition of control strategies to be adopted to evaluate the feasibility of operation of a microgrid when it becomes isolated. Normally, the microgrid operates in interconnected mode with the MV network, however scheduled or forced isolation can take place. In such conditions, the microgrid must have the ability to operate stably and autonomously. An evaluation of the need of storage devices and load-shedding strategies is included in the paper.

Abstract
Portugal is committed towards the EU to an ambitious target of attaining 39% of renewable energy production by 2010, as defined in the RES Directive. The new big hydroelectric investments, together with the mini-hydro power stations that are expected to be ready until 2010 will not be able to increase largely this share of needed renewable energy. The missing renewable energy should be produced exploiting wind energy, meaning that by 2010 a wind power capacity of more than 4.000 MW should to be in operation. At the same time Spain is also increasing wind power integration, such that by 2010 more than 13.000 MW are expected to be installed. The Spanish and the Portuguese electric power systems are facing at the same the challenge of a regional electricity market - the Iberian Electricity Market. This requires that wind power integration must be tackled having in mind technical and commercial concerns.