High and low voltage switchgear is a kind of equipment connected to high voltage or low voltage cables, which can use the transformer to convert the high voltage voltage in the line into low voltage electricity, and then the low voltage cabinet will send the electric energy to the distribution box of each electricity to complete the voltage conversion. The general power supply bureau and substation all use high-voltage cabinets, and then the transformer depressurizes to the low-voltage cabinet, and the low-voltage cabinet then goes to the distribution box of each power supply. During the installation of the high and low voltage switchgear, it is necessary to strictly follow the safety technical operation process to prevent installation errors. According to the installation process of high and low voltage switchgear, the problems that need attention in each installation link are described separately.

1 Check the assembly of the switch cabinet

In theory, the cabinet assembly of the switchgear must meet the requirements of the design drawings, but because there is a certain error in the production and processing of the various parts of the switchgear, the cabinet assembly is also appropriately relaxed requirements, such as the diagonal size deviation as long as it is maintained at no more than 2mm, it can be considered to meet the requirements of the design drawings. In addition, the dimensional accuracy of the installation parts involving the key or precision parts of the cabinet must also be strictly in accordance with the relevant requirements. Secondly, when the various components are connected to each other, it is necessary to ensure that the connection installation sequence is correct, and pay attention to the quality problems of the connecting rod to ensure the overall stability of the cabinet.
Thirdly, when the cabinet is installed, simple operation testing should be carried out, such as opening the door of the cabinet to check whether the opening Angle of the door is equal to or greater than 90°; There is no obvious shaking in the process of opening or closing the door; Whether there is insufficient lubrication of the door shaft, making harsh metal friction noise. After checking the hardware facilities and ensuring that there are no obvious quality problems, you need to optimize the support, connection cables, and other components that may have potential security risks, such as adding insulation covers and adding cable inlet and outlet ports to ensure safe operation of the switch cabinet.
Finally, when the above inspection is over and there are no quality and safety problems, clean up the tools and debris in the switch cabinet, and wipe the internal and external surfaces of the switch cabinet with cleaning tools to ensure that there is no oil stains and dust. SPR-CN-S1 intelligent dehumidifier for switch cabinet dehumidification
2 Check the installation of components in the switch cabinet
The types of components inside the switch cabinet are more complex, and the number is more, but generally speaking, it is nothing more than some protection components such as switch circuit breakers, so when checking this part of the components, we should pay attention to the following points: First, count the types and quantities of components to ensure that the materials are complete, and then compare the components according to the specific requirements of the design drawings to see whether their models and quantities meet the standards. The wrong model should be replaced in time, and the insufficient quantity should be completed in time. Second, the components are installed in strict accordance with the relevant operation process to ensure that the installation position and installation method of the components meet the standards, and ensure that the wires connected with the components are as flat and straight as possible to avoid overlapping and crossing of the lines. Thirdly, the space distance between components and components and between components and the cabinet should be reasonably arranged to prevent the distance from being too large and the connection wire from being too long, increasing the probability of line failure; And to prevent the distance is too small, the operation is not convenient. Fourth, after the installation of all components, compare the design drawings to confirm the correctness of the power test to ensure the normal connection between each component. Fifth, do a good job of cleaning up after installation. During the installation of components, a large number of wires, parts and iron filings will remain, some of which will be attached to the surface or inner layer of the components, so the cleaning work must be careful and careful to ensure that the details are clean.

3 Check the secondary cable connections in the switch cabinet
First, ensure that the component identification and terminal loop name identification are complete, correct, neat and beautiful, and meet the requirements. Second, when conducting wire connection of components, it is necessary to ensure horizontal and vertical in accordance with the requirements of the electrical equipment connection process, and try to make the line beautiful. Third, the electrical gap and creepage distance in the secondary circuit should meet the technical requirements of the secondary wiring construction. Fourth, the wire passes through the metal partition, the bus, the instrument door line to the fixed point, etc., the secondary line should be protected. Instrument door line length is moderate, so that the door open and close freely. Fifth, the size and specifications of various types of copper connectors are in line with the wiring methods of component terminals. Sixth, use crimping pliers to flatten the terminal end of the copper joint, and then connect the terminal end to the terminal post. Pay attention to ensure the correct connection mode, while the degree of crimping is moderate: not only to prevent the pressure line is too tight, the line is prone to aging fracture in the later period of use; It is also necessary to prevent the pressure line from being too loose, and the wire head and terminal post fall off in a short time, resulting in a broken connection. Seventh, the length of the left wire is moderate and the fixed position is unified. Such as ground wire, N wire, power line, etc. can be used about 6mm diameter of the metal round object, the wire around 3 to 5 times; The secondary cable connection must be constructed according to the diagram, the cable connection is correct and meets the requirements of the drawing, and the reserved position of the terminal cable is correct and uniform.

4 Check the installation of the switchgear mechanism
High voltage circuit breaker, low pressure drawer and other moving contacts, with a moderate amount of neutral lubricating oil; Circuit breaker, low-voltage drawer in and out of the operation is flexible, no stuck phenomenon. The high and low pressure mechanism and guide rail are installed correctly and fixed reliably. The ground switch and opening are flexible, and the closing and opening mark are correct. The ground knife edge has neutral lubricating grease.