What is a high-voltage switchgear?

Armored Switchgear (Type K): The cabinet is enclosed by metal sheets with a high protection level, generally up to IP4X. The functional units such as the Circuit Breaker compartment and the busbar compartment are isolated from each other, providing good safety. It is often used in large power systems with high requirements for safety and reliability.​

Compartmented switchgear (Type J): The functional units are separated by metal partitions. The structure is relatively simpler than that of armored switchgear, and the cost is lower. It is suitable for medium and small-sized power distribution systems.​

Box-type switchgear (Type X): It has a compact structure and a small volume, suitable for installation in places with limited space. However, the protection level is relatively low and it is commonly seen in small high-voltage systems or scenarios with strict space requirements.​

Incoming line cabinet: It is mainly used to receive electrical energy from the power grid. Usually, circuit breakers, disconnectors, current transformers and other equipment are installed to introduce the electrical energy of the power grid into the busbar system inside the switchgear.​

Outgoing line cabinet: It is used to distribute the electrical energy in the busbar system to each power consumption circuit. Generally, circuit breakers, current transformers, relay protection devices, etc. are equipped to control and protect the outgoing line circuit.​

Bus coupler cabinet: In a single-busbar sectionalized or double-busbar system, it is used to connect two sections of busbars to meet the needs of different operating modes or selectively cut off the load in case of a fault. The main equipment includes circuit breakers, disconnectors and bus connectors.​

PT cabinet (Potential Transformer cabinet): It is equipped with potential transformers, fuses and other equipment, used to measure the voltage in the circuit, provide voltage signals for relay protection devices and monitor the voltage quality of the power grid.​

Capacitor cabinet: It contains capacitor banks, reactors, switching switches, etc., mainly used for reactive power compensation, improving the power factor of the power grid, reducing line losses and improving power quality.​

Voltage level: Determine the appropriate rated voltage according to the actual power demand of the usage scenario. Common voltage levels of high-voltage switchgear are 3.6kV, 7.2kV, 12kV, 24kV, 40.5kV, etc.​

Functional requirements: Clarify the specific functions of the switchgear in the power system, such as incoming line, outgoing line, bus coupler, PT measurement, capacitor compensation, etc., and then select the corresponding functional type of switchgear.​

Operation mode: The operation modes include manual and electric. For occasions with frequent operations or high requirements for operation convenience, electric-operated switchgear can be selected; while for some simple occasions with low operation frequencies, manual operation can meet the requirements.​

Short-circuit withstand capacity: According to the maximum short-circuit current that may occur in the power system, select switchgear with sufficient short-circuit withstand current and peak withstand current to ensure that when a short-circuit fault occurs, the switchgear can safely cut off the fault current and protect the safety of equipment and personnel.​

Protection level: Consider the usage environment of the switchgear, such as indoor, outdoor, humid environment, dusty environment, etc., and select products with corresponding protection levels. For example, in places with a lot of dust, switchgear with a higher protection level should be selected to prevent dust from entering the interior and affecting the normal operation of the equipment.​

Brand and quality: Give priority to well-known brands and products with a good reputation. These products are usually more guaranteed in terms of design, manufacturing process and material selection. The reliability and stability of the equipment are higher, and the later maintenance cost is relatively low. At the same time, ensure that the products comply with relevant national and industry standards, such as GB 3906 "AC metal-enclosed switchgear and controlgear for rated voltages from 3.6 kV to 40.5 kV".​

Installation environment: Choose a dry, well-ventilated place without corrosive gases and flammable and explosive substances to install high-voltage switchgear. Avoid installing in basements and other places that are prone to water accumulation, as well as areas close to heat sources, water sources or strong electromagnetic field interference. At the same time, the ground of the installation site should be flat and firm enough to bear the weight of the switchgear.​

Foundation construction: Before installing the switchgear, foundation construction should be carried out according to the design requirements. The installation of the foundation channel steel should be horizontal and firm. Its top should be a certain height above the ground (generally about 10mm) and a good grounding connection should be made. The flatness and straightness errors of the foundation channel steel should meet the requirements of relevant standards to ensure the stability and verticality of the switchgear after installation.​

Equipment handling and positioning: When handling high-voltage switchgear, pay attention to protecting the equipment from collision and damage. Use appropriate lifting equipment and tools and operate according to the handling marks of the equipment. Accurately position the switchgear on the foundation channel steel, adjust its position and verticality, and then fix the switchgear to the foundation channel steel firmly by bolts or welding. When multiple switchgears are installed side by side, ensure that