Abstract
The development of small-scale power generation units based on biomass gasification is an effective mean to meet the growth interest of deployment of local power generation exploiting endogenous renewable energy sources. However, significant research and development activities are required towards the deployment of cost-effective solutions suitable to be used in several applications and with different biomass feedstock. For this purpose, a flexible experimental setup is required to be developed. This paper proposes a critical review of the current state of the art of the available technologies suitable for small-scale power generation using biomass gasification. The main guidelines to develop cost-effective solutions are identified and the conceptual framework of the experimental setup is proposed. Also, the operational specifications are presented.

Abstract
This paper addresses the design, development and experimental tests of a prototype of fuel gas generation system based on biomass gasification for small-scale applications, around 5?kW. It comprises the small scale downdraft gasifier and the gas cleaning system aiming to clean-up the producer gas to be used in the upstream Internal Combustion Engine (ICE). The design of the downdraft gasifier prototype follows the methodologies that have been reported on the available literature. However, since these methodologies apply to gasifiers with larger rated powers, the adopted methodology is based on the extrapolation of the main parameters used for larger gasifiers design. For runing the ICE the producer gas requires to have a specific gas composition with an acceptable range of impurities. Therefore, a clean-up system was proposed following three stages: in first instance a hot gas clean-up using a cyclone designed to eliminate particles and compounds; then a heat exchanger was used for cooling the gas to condensate tars and water; finally a cold gas clean-up is performed by filtration using two filter steps: the first one using organic material (biomass) and the second one using a polypropylene cartridge filter. Experimental tests were performed using the developed imbert downdraft gasifier prototype, using pellets as feedstock. The preliminary results allow verifying several drawbacks that will difficult an effective integration of the developed prototype for small scale power generation applications based on ICE using low density feedstock.

Abstract
The paper describes some of the initial results of the CIGRE Working Group C4.605 "Modeling and aggregation of loads in flexible power networks". One of the tasks of the working group is to provide recommendations on developing equivalent static and dynamic models for clusters of diverse loads/generators, i.e., models of distribution network cells and microgrids and recommendations on procedures for data/response gathering and processing. This paper focuses on critical review of existing literature on aggregated models of wind-based generation, active distribution network cells and microgrids for power system studies. © 2011 IEEE.

Abstract
This paper describes technical solutions based on advanced control functionalities for photovoltaic systems aiming to prevent voltage rise above technical limits in low voltage MicroGrids by limiting the injected active power. Due to the action of Maximum Power Point Tracking (MPPT) systems, it is expected that the output power of photovoltaic systems tracks the maximum value according to both solar and temperature conditions. Hence, limiting the active power to be injected into the low voltage network requires the accommodation of the generation surplus. An innovative approach is proposed for this purpose, exploiting a modified MPPT algorithm that finds a proper operation point considering also the grid operating conditions. The technical feasibility of this approach is evaluated through numerical simulations performed in the Matlab (R)/Simulink (R) simulation tool using the detailed models of the power electronic converters.

Abstract
The aim of this work was the development of a new approach to find an optimal solution for the internal electrical network configuration of a wind park. The new approach, described in this paper, allows solving the electrical design problem of a wind park, trying to find simultaneously the best topology for the network and for the cable speciifciations. The problem is considered as a global optimization problem (minimisation of the investments and operation costs), in which reliability is also taken into account. For that purpose, an evolutionary approach based on nitching type methods was used to develop a design tool able to find a reduced set of good solutions to be presented to the design engineers for further decision. This approach was tested with success in the project of a real wind park and the results proved to be satisfactory.

Abstract
High penetration of renewable energies presents a new challenge for conventional power system. Such penetration of renewables resulted in renewed interest in load modeling which may include small renewable generation as a portion of loads. A new CIGRE working group was established to provide guidance with respect to load modeling of new types of load including renewables using measurement data and historical data. This paper summarizes major results of the work of this WG after two years' activities. Although the deliverables are not fully completed, beneficial recommendations of the load modelling such as selection of load model structure, picking up suitable data, proper approach for deriving load model parameters, requirement of measurement data, etc. are introduced in this paper identifying clearly advantage and disadvantage of various load modelling approaches.