<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Under normal operating conditions, a MicroGrid is interconnected with the medium voltage network; however, in order to deal black start and islanded operation following general blackout, an emergency mode must be envisaged. A sequence of actions conditions checked during restoration stage are identified tested through numerical simulation. Voltage frequency control approaches, inverter modes,...

Abstract Large scale integration of distributed generation both medium and low voltage (LV) networks can be achieved by exploiting the Multi‐MicroGrid (MMG) concept, a new distribution system architecture comprising hierarchical control system, which allows coordination among units MicroGrids (MGs) therefore operation such in islanded mode. After general blackout MMG capabilities also used to provide service restoration systems. A procedure for MMGs black start is then addressed this paper....

Under normal operating conditions, a microgrid (MG) is interconnected with the medium voltage (MV) network. However, planned or unplanned events like maintenance faults in MV network, respectively, may lead to MG islanding. In order deal islanded operation and even black start following general blackout, an emergency mode must be envisaged. Two possible control strategies were investigated are described this paper operate under mode. A sequence of actions for well succeeded procedure,...

Large deployment of distributed generation into distribution systems brings new challenges regarding the shift from passive to active control paradigm. These have been extended field dynamic equivalence. Developing effective reduced order models for network cells and stability studies require a careful evaluation techniques that used in conventional power systems. Thus, survey existing approaches is presented this paper. Also critical overview provided their application microgrids. Technical...

Large deployment of microgrids will have a considerable impact on the future operation electrical networks and greatly influence power system dynamics mainly at Medium Voltage (MV) level whenever upstream has been lost. In dynamic studies whole cannot be represented in detailed manner because huge dimension would require very large computational effort. Therefore equivalents for need to derived. The proposed approach is based identification theory developing microgrids, which are able retain...

Large deployment of Plug-in Hybrid Electric Vehicles (PHEVs) will put new challenges regarding the power systems operation. The MicroGrid (MG) concept can be exploited to support progressive integration PHEVs into Low Voltage (LV) networks by developing smart charging strategies manage batteries procedures in order avoid reinforcements grid infrastructures. Assuming that a number owners allow managing when their cars are parked, this paper proposes an approach aims find suitable individual...

This paper presents a general overview about the system operation, management and control following large scale integration of renewable energy sources, focusing in particular wind generation, both onshore offshore. Regarding operation distribution networks, sources other distributed generation systems requires adoption active structures. These structures will contribute to extend intelligence from transmission aiming change paradigm passive towards smart grids vision for European networks...

This paper presents a long-term impact evaluation algorithm to assess advanced under frequency load shedding (UFLS) schemes on distribution systems with intentional islanding of distributed generation (DG). The is based combined discrete-continuous simulation model which utilized verify the effect reliability indices such as system average interruption index, duration and energy not supplied. Moreover, polynomial neural network-based approach implemented support DG in order illustrate...

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

This paper describes technical solutions based on advanced control functionalities for photovoltaic systems aiming to prevent voltage rise above limits in low MicroGrids by limiting the injected active power. Due action of Maximum Power Point Tracking (MPPT) systems, it is expected that output power tracks maximum value according both solar and temperature conditions. Hence, be into network requires accommodation generation surplus. An innovative approach proposed this purpose, exploiting a...

This paper proposes technical solutions that can be implemented in variable speed permanent magnet synchronous generators driven wind turbine systems aiming to mitigate high voltage problems low MicroGrids by controlling the active power output. Due limited control capability of these systems, output prevent rise will require local accommodation generation surplus. For this purpose, additional functionalities are developed integrated electronic based interfaces. Their performance is...

Using Voltage Source Converter (VSC) based High Direct Current (HVDC) technologies, in a Multi-terminal dc (MTDC) system, has been envisaged as an attractive solution for connecting the large offshore wind farms that have planned to meet EU renewable energy targets. The control and operation of VSC-HVDC technologies comprise number challenging tasks, aiming assure effective integration MTDC systems ac transmission systems. Stability studies play key role within this framework Among them,...

This paper addresses the design, development and experimental tests of a prototype fuel gas generation system based on biomass gasification for small-scale applications, around 5 kW. It comprises small scale downdraft gasifier cleaning aiming to clean-up producer be used in upstream Internal Combustion Engine (ICE). The design follows methodologies that have been reported available literature. However, since these apply gasifiers with larger rated powers, adopted methodology is extrapolation...

The continuous growth of wind energy integration on electrical networks has led many utilities to impose fault ride-through capability farms. This means that turbines must remain connected the system during severe occurrence. Regarding existing farms equipped with fixed speed induction generators directly grid, is commonly assisted dynamic compensation devices, such as DSTATCOM units. These power electronic devices are controlled for voltage regulation purposes and behave like a balanced...

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

This study evaluates the transient behaviour of pole-mounted distribution transformers (DT) following fast-front lightning strikes arising medium-voltage (MV) network and low-voltage (LV) network. The effects installing surge protection devices (SPD) in LV terminals DT are also evaluated. For these purposes, studies were performed using EMTP-RV software. results obtained demonstrate effectiveness SPD transformer for improving its safe operation overvoltages.