Reliable Electricity Generation in RES-Based Microgrids

Introduction

Among the many directions and ways of development of modern energy, it can be singled out two tendencies, which have become especially active recently. This is the formation of a global energy system, on the one hand, and the all-round development of distributed energy production, on the other. The realization of both these tendencies is hard to imagine without a large-scale use of renewable energy sources (RES), which step by step consistently occupy more and more significant positions in the world energy balance.

The formation of a global energy system based on RES occurs consistently through building large solar and wind power stations which are gradually moving to large regional and interregional systems (Strebkov & Kharchenko, 2011). There were published proposals for the creation of a global solar power plant that can work 24 hours a day and cover the global electricity demand all year round. The work of Strebkov & Irodionov (2004) proposes a model for the future development of world energy based on direct conversion of solar energy at solar power plants. The plant consists of three large solar power plants connected by special power transmission lines. The work of Strebkov et al. (2018) consideres the transfer of transcontinental energy flows by means of resonant waveguide technologies invented by N. Tesla.

No less important direction of the development of world energy is distributed energy based on the universal construction of individual sources of energy generation needed to supply facilities at the place of production. This direction of energy development is the most interesting for the agricultural sector (Camblon et al., 2009; Alhelou et al., 2018; Alhelou et al., 2016; Alhelou et al, 2015). Power supply of agricultural facilities has a number of specific features: the dispersal of consumers, small unit capacity, the large length of electric, thermal and gas networks, the presence of large sparsely populated areas where agricultural production is conducted and centralized electric and heat supply are absent. Ensuring reliable energy supply of these territories is a task of primary importance.

The reliability of power networks, minimization of energy losses and high economic efficiency of these networks play a significant role (Vinogradov et al., 2018; Vinogradov et al., 2019; Njenda et al., 2018; Zamani et al., 2018). The use of a microgrid formed mainly on the basis of renewable energy sources (RES) is a modern form of realization of the concept of distributed energy and is of great importance for solving the problem of sustainable power supply to agricultural producers.

It is generally accepted that the term “Microgrid” was first introduced by Professor Robert Lesseter in the University of Wisconsin. According to R. Lasseter the key feature of the microgrid is its ability to separate and isolate itself from the centralized power grid in the event of problems with power supply in order to ensure uninterrupted power supply inside the microgrid without power outage. This should be done in accordance with the concept of the network for CERTS (Consortium for Electric Reliability Technology Solutions) with minimal impact on the power within the microgrid. When the state of the network is normalized the microgrid has to automatically reconnects to the centralized network without interruptions in power supply.