Abstract
This paper describes part of the research developed by the Power Systems Unit of INESC Porto in the scope of the MoreMicrogrids EU financed project (under the Contract No: PL019864). In this project, and apart from other issues, it was investigated how microgrid agents could participate in a more effective way in electricity markets. In this paper we present models to enable the participation of microgrid agents in the provision of ancillary services, namely reactive power/voltage control, active loss balancing and demand interruption. This participation is accomplished after running the day-ahead market and it corresponds to the activation of a specific market to allocate these services. The implementation of this kind of models can contribute to create a new stream of money to microgrid agents so that they can integrate themselves in a more natural way in power systems, eventually eliminating subsidized tariffs that represent in several countries an increasing amount of the final end user tariffs. Finally, the paper includes a Case Study to illustrate the use of the developed approaches. © 2010 IEEE.

Abstract
The scheduling of preventive maintenance actions of generators is not a new problem but gained in recent years a new interest with the advent of electricity markets. In this paper we report the research on this topic developed during the preparation of the MSc Thesis of the second author. In this paper we formulate the problem as a mixed integer optimization problem and we describe the use of Simulated Annealing to solve it. Simulated Annealing is a very appealing metaheuristic easily implemented and providing good results in numerous optimization problems. The paper includes results obtained for a Case Study based on a realistic generation system. This research work was proposed and developed with the collaboration of the third and fourth authors, from EDP Produção, Portugal.

Abstract
MicroGrids represent a new paradigm for the operation of distribution systems and there are several advantages as well as challenges regarding their development. One of the advantages is related with the participation of MicroGrid agents in electricity markets and in the provision of ancillary services. This paper describes two optimization models to allocate three ancillary services among MicroGrid agents - reactive power/voltage control, active loss balancing and demand interruption. These models assume that MicroGrid agents participate in the day-ahead market sending their bids to the MicroGrid Central Controller, MGCC, that acts as an interface with the Market Operator. Once the Market Operator returns the economic dispatch of the MicroGrid agents, the MGCC checks its technical feasibility (namely voltage magnitude and branch flow limits) and activates an adjustment market to change the initial schedule and to allocate these three ancillary services. One of the models has crisp nature considering that voltage and branch flow limits are rigid while the second one admits that voltage and branch flow limits are modeled in a soft way using Fuzzy Set concepts. Finally, the paper illustrates the application of these models with a Case Study using a 55 node MV/LV network.

Abstract
This paper presents a conceptual framework to enable a successful integration of Electric Vehicles (EV) into isolated power systems. The developed framework includes the management and control actions that might be implemented over EV in order to improve the system's resilience. Several dynamic stability simulations were performed, using a small isolated grid as a test system, in order to demonstrate the possible contributions EV may provide to fast power/frequency control, either as a highly flexible and controllable load and/or as an energy storage device.

Abstract
Under normal conditions, the MicroGrid operates interconnected with the upstream medium voltage network. However, scheduled or forced isolation can take place. In such conditions, the MicroGrid must have the ability to operate stably and autonomously, requiring the development of suitable control strategies in order to enable MicroGrid islanded operation. The MicroGrid power sources can also be exploited in order to locally promote a service restoration strategy following a general blackout. A sequence of actions for the black start procedure is also identified and it is expected to be an advantage for power system operation in terms of reliability as a result from the presence of very large amounts of dispersed generation in distribution grids.

Abstract
This paper addresses issues concerning the integration of single-phase charging devices for electric vehicles (EV) in low-voltage microgrids Fast release energy storage is a key issue for microgrid islanding operation. EV batteries provide an additional storage capacity, which can now be exploited in order to improve MG islanding Aiming to do so, different control strategies were developed and tested (1) a local control approach where no communication link is required and (2) a centralized charging control solution The local control approach is based on the measuring of EV terminal voltage and frequency in order to define the charging or discharging rates of the batteries The centralized control strategy allows balancing single-phase loads connected to the microgrid by adapting the charging rates of the EV storage devices. Simulation results show that EV batteries can actively contribute for voltage balancing and frequency control during islanding operating conditions