Abstract
In this paper several concepts related to the application of Monte Carlo simulation to evaluate reliability indices of composite power systems are reviewed. In the sequence of previous papers, one integrates in the Monte Carlo simulation a DC Fuzzy Optimal Power Flow model to cope with uncertainties in peak loads. This general framework is now enhanced as one can specify fuzzy load duration curves, uncertainties in repair and failure rates and can adopt either non-chronological or chronological sampling strategies. This package can thus be used to evaluate the impact in the expected values of Power and Energy Not Supplied of uncertainties affecting several variables and parameters.

Abstract
In this paper it is studied and analysed the transient stability of a test power network, considering the tripping of one or more generators. It was used the software package TRANsySTEM that the authors developed for transient security assessment of a multimachine power system. These computer programs use the extended equal area criteria formulation. The results obtained with this direct approach were compared with the solutions produced by the Runge-Kutta method. It is also analysed the influence of the sudden increase in the electromagnetic torque in the rotor shaft fatigue life of the remaining generators, when one or more power units are tripped. Finally, some conclusions that provide a valuable contribution to the understanding of the transient security assessment of a multimachine power system are pointed out.

Abstract
The fast development in electrical power networks and his consequent complexity, impose a more useful state estimation operational scheme, shortening the time interval between consecutive state estimations. Technical developments in distributed Energy Management Systems (EMS), based on fast data communication networks, open up the possibility of Parallel and Distributed State Estimation implementation. In this paper will be introduced and discussed some ideas for the implementation of Parallel ana Distributed State Estimation in electrical power systems. Will be boarding a solution methodology based on conventional state estimation algorithms applicable in local networks and will be analysed some results obtained with a IEEE test system so that we can appreciate the performances of the proposed method. An evaluation of the degree of natural decoupling in the state estimation problem is also performed, and will be compared with the results of computational experiments with standard WLS methods, in the integral and distributed version.

Abstract
In this paper we develop a theoretically robust and computationally efficient state estimator algorithm, to solve the WLS problem by using parallel processing. Technical developments in distributed Energy Management Systems (EMS), based on fast data communication networks, open up the possibility of Parallel Processing in the state estimation algorithms. We have analysed the computational aspects of the parallel processing. Moreover, we have simulated this state estimator parallel algorithm in the IEEE 30, 57 and 118 bus systems. The numerical accuracy of the simulation demonstrates the excellent computational performance of the parallel algorithm. Results of computational experiments are compared with standard WLS methods, in the integral and distributed version. An evaluation of the degree of natural decoupling in the state estimation problem is also performed. The results of computational experiments indicate that a distributed processing for state estimation, is the better way to adopt the parallel computing in power systems energy.

Abstract
Simulation is a useful tool which can significantly reduce resources invested during product development. The present paper describes the development of the Vector Control Signal Processing (VCSP) blockset for use with MATLAB/Simuhnk(R). The originality of this blockset consists on the extension of Simulink for design, simulation and prototyping of signal processing algorithms in power conversion systems. The VCSP blockset, consists on a number of newly developed blocks. Together with Real-Time WorkshopTM and a number of other generally available blocks, it takes advantage of the inherent visual programming techniques of Simulink to reach the above goals. Due to its open and flexible nature, this approach is also very useful as a tool for teaching. The work is focused on modelling and simulation for power conversion systems use in the drive of rotating AC machines with vector control methods. By concept, a simulation environment can be examined at different abstraction or hierarchy levels. The approach in this paper is so the formulation of a simulation task at different levels: component level, electric circuit level, functional description and implementation description. The basic blockset functions are presented and some examples of modelling techniques for both simple and complex drive structures are included. Simulation results are presented and discussed as well.

Abstract
Electrical distribution utilities have been dealing with the problem of estimation of distribution network load diagrams, either for operation studies or in forecasting models for planning purposes. Load curve assessment is essential for an efficient management of electric distribution systems. However, the only information available for most of the loads (namely LV loads) is related to monthly energy consumption. The general procedure uses measurements in consumers to construct inference engines that predict load curves using commercial information. This paper presents a new approach for this problem, based on Kohonen maps and Artificial Neural Networks (ANN) to estimate load diagrams for the Portuguese distribution utilities. A method for estimating error bars is also proposed in order to provide a high order information about the performance of load curve estimation process. Performance attained is discussed as well as the method to achieve confidence intervals of the main predicted diagrams. © Springer-Verlag Berlin Heidelberg 1997.