Fundamental characteristics of distributed power systems and usage patterns of renewables in such systems are considered in the chapter. The chapter presents a full description of a hybrid power complex consisteing of renewable power sources, converters, energy storages, heat and electricity transmission and distribution devices, controlled electrical and heat consumers, etc. Special features of wind, solar, and hydro power plant operational states at self-balanced hybrid power complexes are given. A description of controlled consumers characteristics is presented as well as capability of consideration of hybrid complex being MicroGrid under their influence. The chapter also prescribes examples of technical and economical features of hybrid power complexes of different structures, their future design, and development.
TopIntroduction
Electric power industry one of the main branches of the Russian economy. It provides demand of electricity and heat for population and the national economy, and exports electricity to foreign countries. The sustainable development and reliable functioning of this industry are important factors of its development that define energy security of the country.
The unified energy system (UES) of Russia consists of a number of regional power grids. All power systems are connected by intersystem high-voltage transmission lines, which ensure their parallel operation. However, there is also a number of areas without connection to UES. Power supply of consumers of these regions carried out isolatedly. Production of electricity in these regions is mostly carried out by autonomous gas-piston, gas-turbine and diesel power stations. Transmission lines of 35 kV and below are represent power grid connections in these areas
Power supply of consumers of sparsely populated areas carried out generally based on generating units (GU) with the drive from internal combustion engines. The cost of 1 kWh of electricity produced by this GU that operating on imported liquid fuel is extremely expensive. It is coming from difficult conditions for the delivery of fuel to power plants. This feature determines the main problems of isolated networks that connected to high cost of electricity, necessity of an annual import of expensive diesel fuel, stocking of significant reserves of petroleum products, etc. There are also many problems caused by operation of diesel power plants in hardly accessible areas.
Main objectives of local power systems modernization determined by concept of energy complex's development and improving of energy efficiency of decentralized systems. Such objectives include: ensuring the reliability of energy supply to consumers of electricity, aimed to improving the quality of life of the population, increasing of efficiency of fuel and energy resources utilization in isolated areas and providing favorable conditions for transition of economy of these regions to the way of maximum energy saving.
Achievement of the specified purposes requires the solution of the following tasks:
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Development of effective measures of power supply systems' development and optimization of generating equipment;
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Joint production of electric and thermal energy by power installations;
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Effective utilization of fuel and energy resources of the region taking into account environmental requirements;
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Maintaining the required level of electric power quality;
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Ensuring of operating parameters of the basic electrotechnical and generating equipment in admissible limits.
Besides, the current condition of power industry of regions that work in isolation from the energy system imposes certain restrictions on the level of economic development and the quality of life of the population of these territories. Therefore, for these regions, the question of finding new sources of energy is very relevant. Such resources of power generation could become the renewable energy sources (RES).
TopBackground
The modern technological concept of the MicroGrid is modification of the 20th century power system (that, as the rule, “transfer” energy from several power generators to a large number of users). It is capable to distribute energy more rationally taking into account the smallest changes in parameters and conditions of supply and demand, and allows link the cost and time of energy consumption. Thanks to the principles of “smart grid” building, the system can react to any fluctuations in its components - generation, distribution and consumption of energy.
The term MicroGrid still has no single generally accepted interpretation. So, in accordance to the interpretation formulated by the European Technology Platforms “MicroGrid” (EPoSS, 2017) understood as “power grid that meet future requirements for efficient and economical operation of power system due to coordinated management and use modern bilateral communications between elements of power grid, power plants, energy storages and consumers”.