Microgrid Technologies. Группа авторов

1.1 shows the universal electricity creation until the end of 2016, and also shows that about 30.28% of the entire power is depicted by means of the renewable sources. The estimation is about 2,017 GW out of 6,660 GW the total global electrical energy capacity. Hydropower takes the 1st position in the production of RE.

Clearly, it is shown in Figure 1.2 that about 16.46% of the total power is supplied by the hydropower. It is 54.34% of the RE. The wind power follows it, which is about 7.3% of the total and 24.15% of renewable sources. Then comes Photovoltaic (PV) power (15.02% of RE), about 4.55% of total power capacity, bio-power (5.55% of RE) is about 1.7%, and others are 0.9%. But in 2016, the newly implemented renewable energy is increased by solar (PV) power (47%), wind power (15.5%) and hydropower (9) compared to 2015 [1].

Figure 1.3 shows the consumption of energy sources like natural gas, coal, renewable sources, nuclear, petroleum and other liquid fuels from the year 1090 to 2040 [2]. According to this, consumption of renewable sources is going to increase by 30% in the duration from 2015 to 2040.

Figure 1.1 The renewable global status report.

Figure 1.2 Consumption of renewable energy sources.

Figure 1.3 Intensification of various energy sources from 1990 to 2040.

      Nowadays, maximum research is going on the utility of renewable energy. Micro-grid integration has taken the maximum concentration of researchers. A micro-grid (MG) is a distributed network that includes different possible distributed resources of energy, which can be considered as a single system, that can be optimizable, means can be balanced with generations and loads with a suitable storage system. It is also capable of doing work independently with or without connection with the utility power grid [3].

A micro-grid is a network or an association of local electrical generation resources connected through a common point known as PCC. The micro-grid has one or more renewable generation units, conventional power generation system, the electrical storage system (ESS), the thermal storage system (TSS), electrical loads, and thermal loads. The conventional power generation system can consist of the micro turbine (MT), diesel generator set, etc. Similarly, in renewable generation units, we can make a photovoltaic (PV) generation system, wind turbines, biomass and hydrokinetic system, etc.There are two manners of operation of a micro-grid namely, connected to grid manner, and the other one is island manner. In GC mode a microgrid is in link with the conventional power grid. It is capable of participating in the energy market as a seller or buyer that can exchange energy with the utility. However, in the islanded manner, micro-grid functions as an autonomous body, as disconnected from the utility network. The island condition occurs due to several reasons such as geographical position on earth, brownout and economic issues.

      Generally, the microgrids face a problem of supplying demand properly due to insufficient energy generation. This problem is because of the irregularity of loads and the RE sources [4]. So, a management system is required to deal with the problem. This management system is called a management system of energy (MSE).

      The management system of energy (MSE) is the collection of different control approaches and different active, ongoing exercises along with hardware and software to mitigate the energy management objectives problems. It is a multiple functionary system. It is a system which distributes the generated power optimally and economically to the load with proper voltage regulation and frequency regulation of the micro-grid. So, we can get a smooth changeover between connected to grid manner and isolated manner of micro-grid systems, according to micro-grid components and real-time load conditions of operation. This system can be used to get high-quality power, sustainability, reliability and environmentally friendly power source.

Due to this, researchers started focusing extensively on MSE strategies for various micro-grids ranging from small home (small scale) to cities or towns (large scale) as shown in the different scales of MG of Figure 1.4.

Exploration has started on a study of the practicability of the parts of micro-grid, and it is modeled by scheduling the DGs, and forecasting the data of environmental conditions such as irradiance of sunray, speed of wind flow and water speed, forecast of energy demand and on availability optimization algorithms in the intention of cost-effective benefits with minimum impact on the atmosphere. Figure 1.5 shows the central micro-grid arrangement and components related to the energy management system. It shows that the research is mainly focused on the resolution of different problems regarding the micro-grid by means of an energy management system.

Figure 1.4 Various ranges of MG.

Figure 1.5 Components of micro-grid.

      This is a review of the different features of micro-grid and management of energy that are presented in various current topics, starting from various units of MG, synchronization of components to the recent optimization methodology with system limitations and objective functions for MSE.

Afterwards, the different configuration and components of micro-grid are deployed in Section 1.2. Here the different structures used in an energy management system with various distributed energy sources, various storage systems and different type of load or the consumer behavior are illustrated. Followed by Section 1.3, it depicts the MG–MSE and different modes of operation. Further, Section 1.4 discusses about the recent techniques and algorithms used for optimization in energy management systems. Finally, Section 1.5 concludes the different sections and further deliberates the strategy for further research in this area.

1.2 Generation and Storage System in MicroGrid

      1.2.1 Distributed Generation of Electrical Power

      In recent years, a great number of researchers are discussing the issues in micro-grids. Nowadays, the verities of micro-grid structures have been presented in the literature. In micro-grid the different distributed generations are utilized because of its geographical characteristic, economic benefits, environmental condition and impact on the surrounding. In Ref. [5], there is a discussion on predictive MSE with its control strategies and communication of micro-grid to the independent utility grid. A 1.5 MW wind energy associated with the battery as a storage system is analyzed.