In this study an isolated microgrid comprising both controllable and uncontrollable sources, like solar, wind, diesel generator, fuel cell, aqua-electrolyser, hydrogen storage and battery is considered. To establish an efficient resource management strategy, a central controller takes the decisions based on the status of the loads and sources. The status is obtained with the help of multi-agent concept (treating each load and source as an agent) through internet using User Datagram Protocol/Internet Protocol (UDP/IP). The decisions are transmitted to the controllable sources to regulate their power output for damping of frequency excursion following a disturbance. A control strategy is adopted to regulate the power output from the battery only during transient, resulting in a floating battery scheme in steady state. This will reduce the ampere hour rating of the battery and can improve the damping of frequency excursion following each load disturbance. In a microgrid with generation rate constraint (GRC), tuning of controller parameters and frequency bias is a nonlinear optimisation problem. Hence, this study attempts to tune the controller parameters using an evolutionary technique named bacterial foraging optimisation (BFO). The tuned gains obtained utilising BFO method give satisfactory frequency excursion following a disturbance in the microgrid.

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The objective of this paper is to control the real and reactive power feed to a grid from a Solid-Oxide fuel cell plant independently. The modification in the thermal dynamic model of the Solid-Oxide fuel cell is carried out to include the simulation time step. The controller performance analysis is done on a fuel-cell model developed in MATLAB/SIMULINK platform. It is found from simulation that the control scheme proposed is quite capable of controlling the real and reactive power flow from the fuel cell to the grid independently.

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Over the last six decades, reliance of Gulf Cooperation Council (GCC) countries' economy on expatriate workforce has increased incessantly. Majority of private sector workforce in Gulf Cooperation Council (GCC) countries are expatriates. Recent attempts by governments in GCC countries to localise the workforce, through their workforce nationalisation programmes, have offered limited results. Thus dependence on expatriate workforce will continue in near future and GCC countries, short of professionally and technically qualified local workers will need to employee a large number of expatriates to support their economic and social developments plans. This calls for a systematic approach to understand the specific challenges faced by expatriates of different nationalities in GCC countries, so that these challenges can be addressed to enable GCC countries to become a preferred destination for technically and professionally qualified expatriate workers. This paper presents an overview of GCC countries; reasons for their dependence on expatriate workforce; key current challenges faced by expatriates in GCC countries and suggestions for facilitating adjustment of expatriate workers in GCC countries.