High-Voltage Switchgear

May 06, 2025View: 106 Leave a message

As the name suggests, distribution cabinets are used for power transmission and distribution, so they mainly refer to high and low voltage distribution cabinets, also known as high and low voltage switch cabinets. The term "distribution cabinet" that people often refer to is a general term. Any electrical cabinet, such as high and low voltage switch cabinets, capacitor compensation cabinets, phase advance devices, high-voltage liquid resistance soft start cabinets, medium-frequency power supply cabinets, machine tool control cabinets, etc., is called a distribution cabinet. High and low voltage distribution cabinets.

The electricity generated by power plants needs to be transmitted. It is all conveyed through high voltage and then distributed to substations at all levels to reduce the voltage, and finally delivered to users. High and low voltage distribution cabinets are used for distributing electrical energy. Therefore, distribution rooms are built in substations and various factories and residential areas to place distribution cabinets. Each factory and residential area applies for the voltage level and capacity size according to its own electricity demand. If the electricity consumption is high, the applied voltage will be higher. If the voltage sent over is 35KV and connected to the distribution room, there are many voltage levels for electrical equipment in the factory, such as 220V lighting power, 380V power, and 10KV high-voltage motors, etc. Therefore, the distribution room needs to install high and low voltage distribution cabinets to distribute electrical energy. It is then transformed into different voltage levels through a transformer, and then sent to high and low voltage switch cabinets, and finally supplied to various loads.

Electrical equipment used to receive and distribute electrical energy is called a distribution device. The complete set of power distribution equipment takes circuit breakers as the main body, and combines various other electrical components according to the requirements of the main wiring, the controlled object and the characteristics of the main electrical components. It integrates high-voltage electrical appliances, measuring instruments, protection devices and auxiliary equipment, etc. in a certain wiring method to form a complete set of power distribution equipment (also known as high-voltage switch cabinets). It is used in systems such as power generation, transmission, distribution and power conversion. High-voltage switchgear is an integrated unit composed of primary electrical components, secondary control, protection, measurement and adjustment components, electrical connections, as well as accessories and enclosures.

The characteristics of high and low voltage switchgear; High-voltage switchgear has a metal casing (cabinet body), making electrical equipment and current-carrying capacity less prone to dust erosion and dirt, and facilitating maintenance. This advantage is even more prominent for substations and distribution stations located in polluted areas. High-voltage switch cabinets are produced in batches mechanically in manufacturing plants, which makes it easy to achieve serialization and standardization. The power distribution equipment designed and produced in a standardized manner features a compact structure, reasonable layout, small volume, reduced cost, good assembly quality and reliable operation. The installation of electrical equipment and the laying of lines for high-voltage switch cabinets are carried out separately from the construction of substations and distribution substations, which can shorten the infrastructure construction time.

Classification of high-voltage switchgear According to the structural characteristics of the cabinet, it can be divided into open type and closed type. The high-voltage busbar of the open-type switch cabinet is exposed, and the components inside the cabinet are not separated. It has a simple structure and low cost. The busbar, cable head, circuit breaker and measuring instrument of the enclosed switchgear are all separated from each other, making its operation relatively safe and preventing the expansion of accidents. It is suitable for power-consuming units with poor working conditions and high requirements.

According to the fixing characteristics of the components, they can be classified into fixed type and handcart type. All the electrical equipment of the fixed type is fixed inside the cabinet. The circuit breaker and its operating mechanism (sometimes including current transformers, instruments, etc.) of the handcart type switch cabinet are installed on a trolley that can be pulled out of the cabinet, facilitating maintenance and component replacement. The insertable contacts of the circuit breaker inside the cabinet are connected to the circuit fixed inside the cabinet and replace the disconnector. According to the number of busbar sets, it can be divided into single busbar and double busbar. The following power distribution devices generally adopt single busbars. According to their voltage lines, they can be classified into high-voltage distribution equipment and low-voltage distribution equipment.