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Abstract: Voltage regulation is an important task in electrical engineering for controlling node voltages in a power network. A widely used solution for the problem of voltage regulation is based on adjusting the taps in under load tap changers (ULTCs) power transformers and, in some cases, turning on Flexible Alternating Current Transmission Systems (FACTS), synchronous machines or capacitor banks in the substations. Most papers found in the literature dealing with this problem aim to avoid voltage drops in radial networks, but few of them consider power losses or meshed networks. The aim of this paper is to present and evaluate the performance of several multi-objective algorithms, including hybrid approaches, in order to minimize both voltage deviation and power losses by operating ULTCs located in high voltage substations. In particular, a well-known multi-objective algorithm, PAES, is used for this purpose. PAES finds a set of solutions according to Pareto-optimization concepts. Furthermore, this algorithm is hybridized with simulated annealing and tabu search to improve the quality of the solutions. The implemented algorithms are evaluated using two test networks, and the numerical results are analyzed with two metrics often used in the multi-objective field. The results obtained demonstrate the good performance of these algorithms. [Copyright &y& Elsevier]

Abstract: In this paper, the problem of initial alignment for Inertial Navigation System (INS) is discussed. Based on the Lyapunov transformation, INS error model of stationary base is established. Then, the initial alignment for INS can be transformed into the robust filter design problem for linear systems with multiple disturbances. A robust multi-objective filter is constructed for the concerned INS with disturbance rejection and attenuation performance, where the drift estimations are applied to reject the inertial sensor drifts and mixed filter is adopted to attenuate Gaussian noises and norm bounded disturbances. Finally, simulations for stationary base alignment of an Inertial Navigation System are given to show the efficiency of the proposed approach. [Copyright &y& Elsevier]

Abstract: Based on the baseline PI control structure, the control parameters of non-linear ALSTOM gasifier benchmark problem are optimized. Firstly, taking all the input and output limits under three load conditions as constraints, the relative IAE indices at six scenarios are calculated and optimized by using multi-objective optimization algorithm NSGA-II. A set of non-dominated solutions are obtained which facilitate the further improvement on the performance under coal quality change. Then among those non-dominated solutions, the solution with best coal quality flexibility comes to the fore through a selection procedure. The simulation results show that the optimization and selection procedure presented in this paper improves the baseline PI control performance with better dynamic responses and coal quality flexibility. [Copyright &y& Elsevier]