An electrical power system is a network of electrical components deployed to supply, transfer and use electrical energy. An example of an electrical power system is the grid that supplies electricity to houses and industry in a region: this power system is known as grid and can be broadly divided into generators that supply power, Transports The power of the generation centers to the load centers and the distribution system that feeds the energy to the homes and the industries nearby. Smaller power systems are also found in industry, hospitals, commercial buildings and homes. Most of these systems are based on three-phase AC, the standard for large-scale power transmission and distribution throughout the modern world. Specialized energy systems that do not always rely on three-phase alternating current are found in airplanes, electric rail, transatlantic, and automotive systems.
Fundamentals of electrical energy
Electrical energy is the product of two quantities: current and voltage. These two quantities may vary with respect to time (alternating current) or can be maintained at constant levels (direct current).
Most refrigerators, air conditioners, pumps and industrial machinery use AC power, while most computers and digital equipment use DC power (digital devices connected to the network usually have an internal or external power adapter To convert from AC to DC). AC power has the advantage of being easy to transform between voltages and is capable of being generated and used by brushless machinery. DC power remains the only practical option in digital systems and may be more economical to transmit over long distances at very high voltages (see HVDC).
The ability to easily transform AC voltage is important for two reasons: First, power can be transmitted over long distances with less losses at higher voltages. Therefore, in power systems where the generation is distant from the load, it is desirable to step up (increase) the power voltage at the point of generation and then lower (decrease) the voltage near the load. Second, it is often cheaper to install turbines that produce higher voltages than would be used by most appliances, so the ability to easily transform voltages means that this voltage mismatch can be easily handled.
Solid state devices, which are products of the semiconductor revolution, allow transforming DC power to different voltages, building brushless DC machines and converting between AC and DC power. However, devices using solid-state technology are often more expensive than their traditional counterparts, so AC power is still in widespread use.