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.

Abstract
This paper presents an adequacy and security evaluation of electric power distribution systems with distributed generation. For this accomplishment, bulk power system adequacy and security evaluation concepts are adapted to distribution system applications. The evaluation is supported by a combined discrete-continuous simulation model which emulates the distribution system operation. This model generates a sequence of operation states which are evaluated from a steady-state perspective using AC power flow computations. Frequency and voltage stability are also assessed using dynamic simulation in order to verify the feasibility of islanded operation. Simulation results are presented for the RBTS-BUS2-F1 as well as an actual feeder from the South of Brazil. The results emphasize the need to consider adequacy and security aspects in the distribution system assessments, mainly due to the ongoing integration of distributed energy resources.

Abstract
The Smart Vehicle-to-Grid Project at INESC TEC is currently studying the application of matrix converters to implement an isolated bidirectional AC-DC power converter using a single power conversion stage to provide a high-frequency link between the grid and vehicle. The single-stage structure and bidirectional power flow make the matrix converter an attractive solution for the charging applications of electric vehicles. A very brief overview of the matrix converter and its modulation strategy is presented, followed by detailed analysis. The power conversion system performance is investigated in terms of the switching commutation, input filter and input power factor. Simulations and experimental results of a prototype are also presented to further validate the proposed topology and operating principle.

Abstract
In this paper, a proposal for an ancillary services (AS) market framework addressing voltage control in multi-microgrid systems is presented. This var market proposal for MV distribution systems can be adopted to involve Distributed Generation (DG) units and microgrids in AS provision. In the approach that was developed each player is given the opportunity to submit its bid to the var market and the market settlement is performed using an Optimal Power Flow (OPF) formulation in order to minimize the price of reactive power purchased by the Distribution System Operator (DSO). This market is based on var capacity use and runs daily after the scheduling of the generation units for a period of operation of one clay.

Abstract
This paper investigates small-signal stability and decentralized control design for distribution electric energy systems with a large penetration of distributed generators. Two real world distribution systems are studied in this paper. The first system is the IEEE 30-node distribution system and the second one is the distribution system on Flores Island, one of the western group islands of the Azores Archipelago. The Block Gerschgorin Theorem and Liapunov function-based stability criteria are applied to formally state sufficient conditions for small-signal stability. The results illustrate that when the governor control of distributed generators is designed without considering interactions between generators, small-signal instability could occur in the system and even the sufficient conditions for stability would not be satisfied. In the next step, the paper assesses control design to stabilize potentially unstable distribution systems. The main focus is on designing enhanced decentralized control based on the introduced stability criteria. The findings illustrate that implementing the enhanced decentralized control could ensure stability and support a large penetration of distributed generators.

Abstract
This paper highlights findings of the European Commission funded project called MERGE (Mobile Energy Resources in Grids of Electricity). MERGE is a collaborative research project that includes utilities, regulators, commercial organisations and universities with interests in the power generation, automotive, electronic commerce and hybrid and electric vehicle sectors across the entire European Union (EU). This major two-year research initiative began in January 2010. The MERGE project mission is to evaluate the impacts that electric vehicles (EV) will have on the European Union (EU) electric power systems with regards to planning, operation and market functioning. The focus is placed on EV and SmartGrid/MicroGrid simultaneous deployment, together with renewable energy increase, leading to CO2 emission reduction through the identification of enabling technologies and advanced control approaches. In this paper indicative results from the impact of the additional EV load will have in the daily and yearly system load diagrams and in the operation of the transmission and distribution networks of five European countries (Greece, UK, Spain, Portugal, and Germany) in 2020 are presented. General conclusions are drawn.