Abstract
This paper presents an original forecasting methodology for achieving the spatiotemporal future long-term expansion of small power photovoltaic (PV) systems in a region, taking into account the population density, ground usage and the type of small PV power application adopted. This methodology comprises three stages: a first stage based on a suitable PV technological forecasting method with a group of experts; a second stage consisting of an innovative and iterative process based on elimination of the possible numerical inconsistencies achieved in the first stage; a third stage with a new method for achieving PV power density maps, using a geographical information system (GIS), that provides significant quantitative GIS information and visual and geographically-disaggregated representation of future small power PV systems expansion. The proposed methodology is illustrated with a real example for the region of La Rioja, Spain. In this example, four different combinations of PV systems and geographical zones were considered, and they are referred to as four "PV technologies" in the paper. The forecasted period range was 20 years with steps of 5 years. The results offer very valuable information for electric utilities, PV systems sales and installation agents, investors and regional authorities responsible for energy plans.

Abstract
The uncertainties related to when and where electric vehicles will charge in the future requires the development of stochastic based approaches to identify the corresponding load scenarios. This paper describes a tool based on Monte Carlo techniques to be used for distribution grid planning, providing a characterization of possible grid operation conditions, regarding voltage profiles, branch loading, grid peak power and energy losses. A medium voltage network based on real data is used to illustrate the application of the developed methodology.

Abstract
This paper proposes technical solutions that can be implemented in variable speed permanent magnet synchronous generators driven wind turbine systems aiming to mitigate high voltage problems in low voltage MicroGrids by controlling the active power output. Due to the limited control capability of these systems, controlling the output power to prevent voltage rise will require the local accommodation of the generation surplus. For this purpose, additional control functionalities are developed to be integrated in the control systems of the power electronic based interfaces. Their performance is evaluated through numerical simulations performed in Matlab (R)/Simulink (R) environment and considering the detailed models of the power electronic converters. The results obtained demonstrate the effectiveness of the proposed control functionalities.

Abstract
In this paper it was studied the performance evaluation of Doubly-Fed Induction Generator (DFIG) in the analysis of dynamic voltage stability during Low Voltage Ride Through (LVRT) in electric power systems. Two models of wind turbines were analyzed. In one of the models the wind turbines are equipped with pitch control coupled with a Fixed Speed Induction Generator (FSIG) and a shunt capacitor bank. In the other model the wind turbines are equipped with DFIG, crowbar and chopper. To protect the rotor side converter from tripping due to overcurrents in the rotor circuit or overvoltage in the DC link during voltage dips a crowbar was installed in DFIG. Nowadays the most efficient plants use technologies that allow them to stay connected during a fault and to produce again normally after the disturbance The model used can take into account these new technologies. The automatic voltage regulators of the generating units, and the turbine speed governors were modelled in detail. Different load models were used and the under load tap changers were also taken into account. The simulation results were obtained using the EUROSTAG software package. Finally, some conclusions that provide a better understanding of the dynamic voltage stability of a system with FSIG and DFIG models during LVRT are pointed out. © VDE VERLAG GMBH.

Abstract
State estimation plays an important role in real time security monitoring and control of power systems. With increasing implementation of PMUs across the electric power grids and the ability of the Phasor Measurement Unit (PMU) to directly measure the system state, the use of these measurements to improve the precision of state estimator becomes imperative. In this paper, a new state estimator including voltage and current phasors and traditional measurements is proposed. The methodology is validated by simulation results on the 14 and 30 IEEE bus test systems. Several comparisons between the use of SCADA measurements and PMU measurements are exposed. Discussion concerning statistical robustness of the implemented state estimators is presented. © VDE VERLAG GMBH.

Abstract
In this paper it is proposed a technique to identify the relevant neighbouring electric power systems using the Horizontal Network methodology. The relevant network of the Spanish system was established, taking into account the actual interconnections and the new cross-border tie-line in Douro International with a voltage level of 400 kV. All simulations of the Portuguese and Spanish transmission systems were performed using the computational software package PSS®E from Siemens/PTI. The savecases used in this study represent pictures of the real systems. From the simulation results, some conclusions that provide a valuable contribution to the understanding of the impact of the new interconnection between the two countries will be pointed out. © VDE VERLAG GMBH.