Updated: Aug 22, 2020
1. Electric Power Networks
Electric power networks (EPNs) are one of the largest systems built by man. Many thousands of nodes, transformers, transmission and distribution lines, generation plants and a large number of loads are components within these electric systems. A typical Electric Power Network can be divided into three main parts, namely: generation, transmission and distribution, see Figure 1. The main problems in such systems are the balance between generation and the power consumed by loads, voltage balance, reliability and energy quality.
Figure 1: One–line diagram of a typical electric power network.
2. The Evolution of Electric Power Networks
Electric power networks have had many improvements since their emergence in 1880s, Figure 2. The first complete electric network (developed in 1882) was based on the DC theory. However, since electrical energy losses are dependent on the value of the resistance times the square of the current, the voltage level has to be high to minimize losses. DC technology had not developed enough to transmit electric power over long distances at that time. The emergence of AC theory (mainly the AC transformer) allowed the transmission of electric energy over long distances, and as a consequence, the use of DC systems was gradually reduced, and for a long time more attention was paid to the developments of AC equipment. However, advances in power electronics and state solid technology gave the basis for the rise of DC equipment from the 1950’s onward, initially, for high power applications.
Figure 2: The electric power networks evolution.
At present, large parts of electric power networks are based on AC current and their infrastructure is largely based on the same principles as the first power systems constructed 120 years ago. However, in Europe and North America, many power transmission systems are reaching their operational limits and older generation plant is nearing the end of its usable life and will need replacing, leaving room for the interconnection of renewable energy. In Asia, Africa, and Central and South America power networks are expanding rapidly. Additionally, with the introduction of computer systems in the 80’s, loads requiring “Digital Quality” (critical computers systems, data systems, etc.) have increased as well.
3. The Future of Electric Power Networks
It is expected that by 2030, electric energy consumption in the world could increase by about 50%. Other sources forecast that global electricity demand will rise by 65% from 2014 to 2040. About 85% of the electricity rise will be due to developing economies. In order to meet this energy demand, with a sustainable low–carbon electrical power system, a great deal of renewable energy will need to be interfaced and these interfaces are very likely to be power electric devices. Also, many electric infrastructures around the world will need to be refurbished and renewed, and many components will need to be redesigned. Hence, the coming years will necessitate a huge change in the electrical power supply system. Thus, the use of reliable low–carbon electricity generation sources, cost–effective renewable energy sources and demand–side management are becoming important pieces in the energy policy in many countries.
Many countries around the world have started the modernization, upgrade and renovation of electrical power networks with the use of renewable energy, advanced demand side management and distributed generation management, the installation of new meters (called smart–meters), microcontrollers and advanced control methods for the nonlinear loads. The resulting network, with a greater degree of flexibility, better control and more efficiency, is called a “Smart Grid” (others names used are Intelligrid, GridWise, FutureGrid, etc.).
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