Читать книгу Microgrid Technologies - Группа авторов - Страница 30

In Ref. [42] the authors have studied the micro-grid consisting of several renewable energy sources with EMS. They have taken the goal function as the cost minimization of energy, which is the net cost of RES per annual cost of the net energy produced. Now the optimization objective is subjected to various constraints, such as reliability, economic conditions and environmental conditions. The criteria of reliability can be considered as the amount of energy cannot be supplied when the amount of power demand is more than the power generation. In economic condition, all of the cost includes installation cost, running cost. The environmental constraint is about the amount of CO2 emitted related to distributed generation system.Multi-objective optimization has been implemented by the authors of Ref. [43]. They have done the optimization for keeping power balanced in-between generation and utilisation, taking more than one objective functions. The objective functions can be taken, such as bus voltage stability, maximum power extraction from PV panel, maximum battery protection by keeping it in a suitable range of SOC. Reduction in hydrogen consumption minimized the fluctuation.

Figure 1.6 Micro-grid in Islanded mode.

The authors of Ref. [44] have expressed an MSE for the microgrid in standalone style such as solar power or wind power, etc. which has an objective function of cost reduction. The cost of an MG is consisting of the cost of energy injected by the distributed sources, the cost of energy storage unit like the cost of energy during charging or discharging, expenditure on the utilized energy, and the charges of penalty for undelivered power.

In Ref. [14], the authors have developed an MSE for different distributed sources like wind turbine ‘WT’, photovoltaic ‘PV’, plug-in EV ‘PEV’, diesel generator system ‘DGS’ and battery in islanded microgrid. The objective function is to make the best use of the number of adjustable loads during the islanded operation manner. The problem of optimization has been utilised to balance power. The constraints are load, limitation of the power generator and also battery specification.

In Ref. [45], the researchers have specified an idea about a cost-effective structure of thermal power plant. The goal of optimization is to decrease the cost of fuel of the thermal generators, taking consideration of the effect of the loading at the valve’s point. The constraints are power balancing, power generator’s limitations, and the ranges of operation of prohibited generators and its limits of ramp rate.