on a secure supply of energy. With Growing con-
cern about the availability of primary energy, rising
electricity demand, use of renewable energy sources
such as wind and solar become an obligation (Bhoyar
and Bharatkar, 2013). The new generation of electric
networks should integrate renewable energy into the
electrical grid (Hatziargyriou, 2014). Thus, system
security, environmental protection, quality of electric-
ity, cost of supply and energy efficiency should be
considered in new ways to meet the changing needs
in a liberalized market environment. Microgrid is a
contained network of distributed generation sources
and energy storage devices that are connected to the
loads. The generation can be from renewable sources,
that reduce (or cancel) the need to conventional en-
ergy sources. The potential for improving the avail-
ability of Microgrid power supply is one of the main
motivations behind the development and deployment
of microgrids. Because of the importance of the avail-
ability of electrical energy for various applications
and the fluctuating availability of renewable energy
sources, a lot of research are interested in different
kinds of power sources hybridisation and their avail-
ability. The adequate choice of sources is the most
important step to improve availability. The hybridi-
sation can be on the type of sources (renewable or
programmable source, energy storage devices) or on
kind of the same type of source energy storage de-
vices (wind turbine and PV, fast-dynamic storage de-
vices and long-term storage devices, fuel cell, diesel
generator) or on both of them. After an adequate
choice, the sizing of these sources plays a mattering
role in the guarantee of the continuity of service (Lo-
genthiran and Raj, 2010). Many optimizing method-
ologies are proposed to calculate the optimum size of
energy source and storage system considering avail-
ability criterion (Y. Nian and Liu, 2013). Some pa-
pers explores how microgrids availability is impacted
by the different topology design choices for the power
electronic interfaces between the distributed genera-
tion (DG) sources and the rest of the microgrid. This
work focuses on the effect of DC or AC architec-
ture choice, converter design on system availability.
Power management strategy (Wang Haiyan and BiY-
ing, 2011) also have a significant impact on the avail-
ability of electrical energy, especially in the case of in-
sufficient production of energy or hardware problem.
Several research works have been interested in the im-
pact of the strategy of control on the different crite-
ria of microgrid power supply (WANG, 2013), espe-
cially the power-quality and the availability of elec-
trical produced energy (Thang, 2012). Whatever the
approaches of control (centralized/decentralized ap-
proaches) and especially in island mode, they require
Figure 1: Petroleum platform in Gulf of Hammamet in
Tunisia.
forecasting of the generation from renewable power
sources, electricity demand (and heat demand in some
cases). Prediction of the evolution of this quantity al-
lows us to face unsafe situations and optimize produc-
tion costs and power supply availability (H.X. Yang
and Burnett, 2003) (V. and K.U, 2014) . Therefore,
forecasting options may have a direct impact on the
economic viability and supply availability of micro-
grids, since they allow them to enhance their compet-
itiveness compared to centralized generation. To have
a wider degree of freedom on control strategy of elec-
trical power supply distribution in microgrid compar-
ing to the control based on forecasting (V. and K.U,
2014) and the control based on load shedding (Lee
and Huang, 2013), we propose a new optimized con-
trol strategy combining these two aspects by taking
in consideration the priority of the load supply. The
basic idea of our proposed strategy is to use the fore-
casted weather information to predict the availability
of renewable sources of refuelling of programmable
sources in an island microgrid. We aim in this paper
to make the right decision about the achievement re-
fuelling and load shedding.
3 CASE STUDY AND PROBLEM
We will describe in this section the Microgrid archi-
tecture and the climate values and we will introduce
the problem.
3.1 Microgrid Architecture
The Microgrid investigated in this paper is an abstrac-
tion of a petroleum platform (Figure 1) islanded lo-
cated on the Tunisian Coast. This Microgrid concep-
tion adopted for this case study is composed of PV
arrays, a wind turbine, a diesel generator with its fuel
tank, a storage device (batteries) and two loads (Fig-
ure 2). The Microgrid is designed as follows:
• Each renewable energy source (PV, Wind turbine)
is sized to be able to generate the electrical power
supply required by both loads and batteries in
favourable weather conditions,
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