Abstract
The 2001 PowerTech Conference held in Porto, Portugal from 10 to 13 September, provided an international forum for participants to share knowledge, experiences, and new ideas about the changes in the electronic power sector. The Conference was attended by more than 450 delegates from 50 countries.

Abstract
In this paper, CARE an advanced control system for the optimal operation and management of isolated power systems with increased wind power integration, is presented. This control system minimises the production costs through an on-line optimal scheduling of the power units, which takes into account the technical constraints of the thermal units, as well as short-term forecasts of the load and the renewable resources. The power system security is maximised through on-line security assessment modules, which predict the power system capacity to withstand pre-selected disturbances caused by power variations from both the renewable and thermal power sources or from faults.In this paper, CARE an advanced control system for the optimal operation and management of isolated power systems with increased wind power integration, is presented. This control system minimizes the production costs through an on-line optimal scheduling of the power units, which takes into account the technical constraints of the thermal units, as well as short-term forecasts of the load and the renewable resources. The power system security is maximized through on-line security assessment modules, which predict the power system capacity to withstand pre-selected disturbances caused by power variations from both the renewable and thermal power sources or from faults.

Abstract
The classical long range distribution network planning problem consists on deciding network investments to meet future demands at a minimum cost, while attending technical constraints. The decisions whether to construct or reinforce substations and branches lead to a mixed integer programming problem with a great number of decision variables. Besides, the network injections have a fuzzy nature on account of the non availability of statistical data in what concerns future loads (namely in new areas and due to the presence of independent producers. Moreover several objectives must be taken into account. This leads to a fuzzy multiobjective, mixed integer problem. This paper presents a case study, adapted from a real network, that illustrates the application of an integrated methodology to deal with the planning problem. This case study aims into illustrating the proposed methodology and to point out its flexibility to adapt to the planner's needs.

Abstract
This paper presents an enhanced version of an AC Fuzzy Power Flow model designed to integrate correlation data between nodal injections. The model gives the user the possibility to specify fuzzy numbers to represent the possible behavior of loads and generations and outputs fuzzy membership functions for voltage magnitudes and phases, active and reactive flows, losses and generations. The algorithm is organized in two basic steps. The first one corresponds to a linearized procedure while the second aims at introducing correlated data leading to a reduction of the width of the membership output functions. In a final section, we present results obtained with a case study based on a didactic power system to illustrate and highlight details of the proposed models.

Abstract
Unbundling and liberalization of the electric sector has led in many countries, including Portugal, to the settlement definition of quality standards for the power distribution systems that give rise to penalties when those standards are not met. Also, penalties and rewards related to global reliability indices exist in some countries. Distribution companies must take this into account when planning there systems because the minimization of the net reliability cost is a main criteria when making investment decisions performing reliability studies to support investment decisions, and penalties (or rewards) become direct reliability costs (or benefits), regardless of any other consideration concerning the impact of the frequency and duration of the interruptions. Most of the time, standards are defined in terms of the sum of the interruption durations during a year. In this paper, the details of this discussion are addressed, in the framework of the investment decision-making process. A formal model for the problem is proposed, along with methodologies able to tackle it. The inadequacy of a markovian approach is discussed and illustrated, showing how bad investment decisions can be made due to incorrect evaluation of the reliability costs. The discussion will be illustrated with small numerical examples.

Abstract
Defining the needs of operating reserve in a power system has been always a subject of interest, leading to the development of deterministic rules (e.g. the percentage rule defined by UCTE in Europe or the well-known "largest unit" rule) and probabilistic methods like PJM (Pennsylvania-New Jersey-Maryland) and its enhancements, based on the concept of risk. However, the recent increase in the penetration of wind power generation changed the framework of this evaluation, due to the volatile nature of this kind of energy. In this paper, a detailed model of the unavailability of wind parks that accounts both for machine failures and different wind levels is combined with the modified PJM method, in order to build a consistent framework for the evaluation of the operational risk. The paper also shows how the proposed model can be used as a decision-aid tool for planning the operational reserve, either by performing multicriteria analysis on cost and risk or by stipulating an acceptable risk level.