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
This paper investigates dynamic stability and control design of modern electric energy systems as many MW-scale distributed generators (DG) of various types are deployed in the distribution side of electric systems. The paper is mainly concerned about small-signal frequency stability of distribution systems with decentralized or centralized control systems. The Gerschgorin Circle Theory and Hicks Stability Theory are used for verifying sufficient conditions for small-signal stability. The paper also discusses about designing advanced enhancing robustness methods to ensure both safety and stability of modern distribution systems. Finally, the paper closes with a discussion of policies needed to support large penetration of DG units in distribution systems to ensure safety and robustness of the system. ©2010 IEEE.

Abstract
This paper presents a novel architecture for electrical distribution networks based on a decentralized control system where a Substation Automation and Control System plays a key role. This new control element brings additional control and management functionalities that are crucial for future distribution networks with high levels of Dispersed Energy Resources in both interconnected and islanded operating modes. Several coordination and control issues are addressed with the aim of optimizing grid operation in interconnected mode and simulation results are shown for voltage and reactive power control.

Abstract
Ambitious targets for renewable power production have been defined for the electric power systems in Europe. The accomplishment of these targets requires the increase in renewable energy production, namely from wind power generation. However, the intermittent nature of wind creates several problems to the power system operation and new approaches based on the combined use of wind power and energy storage technologies need to be developed. In this paper, the concept of the combined use of wind power production and hydro storage/production is exploited, through the development of an operational optimisation approach applied to a wind generator park with little water storage ability. The optimisation model defines the operational strategy to be followed for the hours ahead by a pump station and an hydraulic generator embedded in a wind/hydro pumping facility, using the Portuguese energy remuneration rules. The proposed methodology leads to considerable yearly profits for the wind generator production.

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
Wind and solar power are well known intermittent power sources with high availability uncertainties. Hence, whenever they are integrated to distribution systems, these power sources can increase significantly the complexity of system operation. This paper presents an impact analysis of distributed energy resources integration on distribution systems, focusing mainly on reliability aspects. Therefore, an interesting algorithm to correctly determine the amount of capacity that may be transferred to other feeders is presented and discussed, taken into consideration the presence of distributed generation. The methodology is tested in a typical Brazilian distribution system, assuming the integration of a diesel-based combined heat and power unit, wind turbines, and solar panels. The results provide general insights regarding the benefits of applying distributed generation to alleviate load transfer restrictions.