Abstract
This paper presents a new hierarchical approach to deal with the problem of controlling frequency and active power generation of a medium voltage network comprising several microgrids and distributed generation sources operated in islanded mode. The hierarchical approach described here should be cost effective and capable of dealing with large numbers of distributed microsources and performing tasks related to coordinated frequency control.

Abstract
This paper describes a new approach for the dimensioning and location of STATCOMs in Grids with large scale integration of wind energy. The approach developed uses as criterion the reduction of the loss of wind generation due to the operation of under voltage relays following a grid disturbance. The methodology adopted exploits Simulated Annealing in the identification of the problem solution. The approach has been tested in Iberian electrical system and results obtained show also its effectiveness regarding the global dynamic behaviour of the system.

Abstract
In this work a methodology is developed of optimization applying to the Simulated Annealing Algorithm, which involves the dimensioning and the localization of STATCMOs at the different buses of the Portuguese grid where there is injection of the wind generation considering the 2009 scenario. With this methodology it is hoped to obtain reactive energy support and consequently improving the voltage values at situations of abnormal grid functioning, as for exemple, at the sequence of a short-circuit In this way it is supplied, to the wind generators capacity of "ride through fault" capability so that the Grid Codes are fulfilled defined by the transmission system operators. The results show how important can be STACOMS contributions in case of failure. Avoiding in many situations that the wind generators protections act due to the regulation of the relays of under-voltage, contributing in this way for the improvement of the dynamic behavior of the whole grid.

Abstract
It is now more than a decade since distributed generation (DG) began to excite major interest amongst electric power system planners and operators, energy policy makers and regulators as well as developers. This paper presents an overview of the key issues concerning the integration of distributed generation into electric power systems that are of most interest today. The main drivers behind the focus on DG integration, especially of the renewable type, in many countries around the world are discussed. A synopsis of the main challenges that must be overcome in the process is presented. Particular emphasis is placed on the need to move away from the fit and forget. approach of connecting DG to electric power systems to a policy of integrating DG into power system planning and operation through active management of distribution networks and application of other novel concepts. The paper also analyses the repercussions in transmission system operation and expansion that result from the connection of large amounts of DG of different energy conversion systems focusing on issues related with impacts in steady state operation, contingency analysis, protection coordination as well as dynamic behaviour analysis. A discussion on the possibility of provision of ancillary services by DG is also included. Some results from studies performed in the interconnected Portuguese transmission system are presented and discussed. Some of the opportunities that could be exploited in support of the integration and hence greater penetration of DG into electric power systems are also explored.

Abstract
This paper proposes a control scheme that allows doubly fed induction wind generators (DFIWG) to participate effectively in system frequency regulation. In this control approach, wind generators operate according to a deloaded optimum power extraction curve such that the active power provided by each wind turbine increases or decreases during system frequency changes. The control strategy defined at the wind generator to supply primary frequency regulation capability exploits a combination of control of the static converters and pitch control, adjusting the rotor speed and the active power according to the deloaded optimum power extraction curve. Results obtained in a small isolated system are presented to demonstrate the effectiveness of the approach.

Abstract
This paper presents an optimization strategy to be adopted at wind park control level. This approach transposes the classical formulations of a unit commitment and a generator dispatch problem to the turbines of a wind park, assuming that variable speed wind turbines are installed, and considering that wind speed forecasts are available. Wind speed forecasts, demands from grid operators or generation levels defined to comply with market strategies are the inputs of the problem. A small example is used to illustrate the proposed approach.