Integrated Electric Power Grid

the combination of two or more electric power systems to supply large territories within the borders of one or more countries. Such a grid generates, distributes, and transforms power (mainly electric power).

An integrated grid has considerable technical and economical advantages compared to single or to partially interconnected power systems, including enhanced reliability of operation and uninterrupted power supply and increased ease of creation of the necessary reserve capacity; integrated grids also promote the integrated use of various types of power (electric, thermal, and so on). An integrated electric power grid is a part of the overall power system of a country. Its large dimensions, complex system interconnections, and purposeful regulation impart to a unified power system the performance characteristics typical of major systems and, with automation, the characteristics of cybernetic systems.

Integrated power grids are studied in power engineering. Development of such a grid is characterized by dependence on the growth of power consumption and on material labor resources. The development of electric power engineering actively influences technical progress and the distribution of the production resources and population of a country.

As of 1971, the electric power systems of integrated grids were connected mainly by high-tension transmission lines of 220, 500, and 750 kilovolts (kV), convertible to 1000–1200 kV of alternating current and 800–1500 kV of direct current. Integrated electric power grids may be of various structures, depending on the type of power plants in the grid (thermal, condensation, hydroelectric, or nuclear power plants, centralized district power plants) and the configuration of the electric networks connecting the power plants with the main areas of power consumption. The creation of an integrated electric power grid promotes the reduction of expenditures for the electrification of districts that are remote from power plants and the improvement of the utilization of power plant capacity, makes practical an increase in the rated power of their units (up to 500–1000 MW), improves the operating economy and reliability of power plants and distribution systems, and facilitates the operation of individual systems in cases of differing seasonal load changes and repair periods. In addition, the joining of power systems located in different time zones reduces the simultaneous total peak load, thus reducing the expenditures required for the construction of peak-load power plants. In connecting systems located at different latitudes, the requirements for the base load are also reduced, since the duration of the maximum load will vary for such systems.

The control of an integrated grid requires, above all, complete automation (including protection against breakdowns) of individual power plants, power grids, and power systems and their combinations. The main problem in this area of technology is the development of methods and devices to produce trouble-free operation and optimum control of the power system. The study and improvement of methods is based on physical and mathematical simulation, with wide use of digital computers, which operate as advisory tools and later, as the system becomes more advanced, as control machines. New automatic control systems that ensure optimum conduct of technological processes, as well as the collection, processing and transmission of all necessary data, are being created and developed.

The control of an integrated electric power grid has three main aspects: day-to-day regulation (traffic control), economic administration, and regulation of the development of the system (short-term, for periods of one to five years; long-range, for periods of 10–15 years; and forecasts, for periods of 20–30 years). The development of an integrated power grid also provides for improvements in the individual power systems and in the system interconnections, which constitute a unified entity. The Integrated Electric Power Grid of the USSR is managed by the State Traffic Control.

The creation of integrated electric power grids is conditioned by the growth of centralization in power production. In the USSR, the power supply is to be 97–98 percent centralized by the end of 1975; by 1980, 99 percent. The construction of the Integrated Electric Power Grid of the European part of the USSR was begun in 1956 with the introduction of the 400-kV transmission line from the V. I. Lenin Volga Hydroelectric Power Plant to Moscow. In 1957 the united administrative office for the power systems of the Central Zone (Moscow, Gorky, Ivanovo, and Yaroslavl oblasts) was reorganized as the traffic-control office of the Integrated Electric Power Grid. In late 1957 the rated power of the Integrated Electric Power Grid reached 8 gigawatts (GW), or 8 million kW; the simultaneous maximum load was 5.6 GW, and the annual consumption of electric power was 33.2 billion kW-hr. In 1970 the electric power generated by power plants connected to the Integrated Electric Power Grid accounted for 71.5 percent of the output of the power plants in the USSR. By 1970, the Integrated Electric Power Grid of the European part of the USSR had become the largest power system in the world. It includes the power-supply systems of the Central Zone, the Northwest, the Middle Volga Region, the Urals, the South, the Northern Caucasus, Transcaucasia, Siberia, and Middle Asia and connects more than 550 power plants. The combined output of electric power in the power systems of the USSR was 740 billion kW-hr in 1970. The Integrated Electric Power Grid of the USSR is connected to the power systems of the member nations of the Council for Mutual Economic Assistance, forming the Peace power grid. The individual power plants and transmission systems of the USSR are also connected to the power-supply systems of Finland, Norway, and Iran.