Views:177 Author:Site Editor Publish Time: 2020-03-10 Origin:Site
Electricity transmission refers to a method of transmitting electricity from a power plant or power source from one place to another. Due to the immature technology of the early days, direct-current power transmission was used and gradually evolved into alternating-current transmission. AC transmission has many advantages, such as it reduces losses in power transmission, increases speed and transmission length. What are the power transmission methods? Below I will introduce you in detail about the principle and process of power transmission.
The transmission of electrical energy, together with transformer, distribution, and power, constitutes the overall function of the power system. Through power transmission, the power plants and load centers that are far apart (up to thousands of kilometers) are connected, so that the development and use of electrical energy can exceed regional restrictions. Compared with other energy transmission (such as coal, oil, etc.), power transmission has the following advantages: small loss, high efficiency, flexible and convenient, easy to regulate and less environmental pollution; at the same time, power transmission can also connect power plants in different locations to implement peak and valley adjustment. Power transmission is an important manifestation of the superiority of electric energy utilization. In modern society, it is an important energy artery.
Transmission lines can be divided into overhead transmission lines and underground transmission lines according to their structural forms. The former consists of line towers, wires, insulators, etc., which are erected on the ground; the latter is mainly laid with cables, which are laid underground (or underwater). Transmission can be divided into DC transmission and AC transmission according to the nature of the current sent. In the 1880s, DC transmission was successfully implemented first, but later it was replaced by AC transmission at the end of the 19th century due to the limitation of low voltage (the transmission capacity is roughly proportional to the square of the transmission voltage). The success of AC transmission ushered in the 20th century electrification era. Since the 1960s, due to the development of power electronics technology, new developments have been made in DC power transmission. Together with AC power transmission, AC and DC hybrid power systems have been formed.
The level of transmission voltage is the main indicator of the development level of transmission technology. By the 1990s, the common transmission voltages in countries around the world were high-voltage power transmission of 220 kV and above 330 to 765 kV, and ultra-high voltage power transmission of 1000 kV and above.
In the power system, a power plant converts natural primary energy into electrical energy and sends it to remote power users. In order to reduce the power loss on the transmission line and the line impedance voltage drop, the voltage needs to be increased. In addition, in order to meet the safety needs of power users, the voltage must be reduced and distributed to various users. This requires a substation that can increase and decrease the voltage and can distribute electrical energy. Therefore, the substation is an electrical device in the power system that transforms voltage, receives and distributes electrical energy. It is an intermediate link between the power plant and the power user. Its role is to transform voltage, transmit and distribute electrical energy.
The substation consists of power transformers, power distribution devices, secondary systems and necessary auxiliary equipment.
The transformer is the central equipment of the substation. The transformer uses the principle of electromagnetic induction.
The power distribution device is a device that connects all the switching appliances and current-carrying conductor auxiliary equipment in the substation. Its role is to receive and distribute electrical energy. The power distribution device is mainly composed of bus bars, high-voltage circuit breaker switches, reactor winding, transformers, power capacitors, arresters, high-voltage fuses, secondary equipment and other necessary auxiliary equipment.
Secondary equipment refers to equipment that measures, controls, monitors and protects the state of the system once. The circuit formed by these devices is called a secondary circuit, which is collectively called a secondary system. The equipment of the secondary system includes a measurement device, a control device, a relay protection device, an automatic control device, a DC system, and necessary auxiliary equipment.
In this article, we understand the principle and process of power transmission. If you have any questions about this product, you can follow Jecsany Electrical Equipment, a company committed to supplying various circuits breakers and switches.