Have you ever stopped to think about how electricity gets in your home sockets? Where does it come from? In Brazil, approximately 90% of our electricity is generated in a hydroelectric plant, these are in rivers, so you must be thinking, well the river closest to my house is in another city or at best a few kilometres away. Well, that’s right, the plants are far from our homes and that electricity has to travel all this distance to reach our outlets. The set of facilities, equipment, structures and companies that make electrical energy reach our outlets is called the Electric Power System ( SEP). The SEP is divided into four parts, namely Generation, Transmission, Distribution and Consumption.
Generation: One of the maxims of physics says that no energy is created but that it is converted, and this is exactly the function of the generation sector, to transform some type of energy into electrical energy. In the case of hydroelectric plants, the gravitational potential energy that translates into the strength of the river rapids is used to rotate the propellers of a generator and convert that force into electrical energy in order to be transported to our outlets. There are other sources to generate electric energy besides the strength of the rapids of a river, such as sunlight, the strength of the winds, chemical and thermal processes.
Dam of a hydroelectric
Electric transmission lines
Transmission: The electrical energy generated has to be transported to our outlets, but due to the nature of the alternating current we use, this process cannot be done using batteries, but it has to be used when it is generated instantly. The transmission process is done through the transmission towers that travel kilometres from the plant where the energy is generated to the proximity of the cities where it will be consumed. In this transport process, due to losses in the route, the voltage of the electricity at the beginning of the line has to be increased sharply compensating for these losses and in the vicinity of the cities again lowered to consumption levels. The elevating and lowering substations are responsible for this process and are installations belonging to the transmission area.
Interconnected electrical transmission towers
Electric transmission lines
Distribution: Distribution is what we consumers understand as the company that sends the electricity bill every month, as this company is the concessionaire that manages electrical distribution in neighbourhoods, cities and states. Not every concessionaire, as in the case of Minas Gerais, CEMIG, is responsible for generation, although most of them are, they are different sectors that may or may not belong to the same company. The concessionaire responsible for the distribution sector is the one who makes direct contact with the final consumer, like us, it is responsible for placing poles on the streets, cables connecting the poles and our house or our industry and company and also for charging us about the service of electricity.
Electrical distribution system
Posts for urban electrical distribution
Consumption: We are the users of electricity in homes, industries or businesses. From the energy meter to our homes, we consumers are responsible for ensuring the correct use of electricity, as well as consumption in a conscious and responsible manner.