What issues should be noted in the installation of high and low voltage switchgear

There are many issues that should be paid attention to during the installation of high and low voltage switchgear, and various inspection work should be done well. The installation of high and low voltage switchgear is a complex and systematic task. Only by conducting distributed inspections to ensure that every step is free from misoperation, can the normal operation of various functions of the high and low voltage switchgear be ensured to a greater extent.

1. Assembly inspection of switchgear cabinet body

In theory, the cabinet assembly of the switchgear needs to meet the requirements of the design drawings. However, due to certain errors in the production and processing of various components of the switchgear, the requirements for cabinet assembly have also been appropriately relaxed. For example, as long as the diagonal dimension deviation is maintained at no more than 2mm, it can be considered to meet the requirements of the design drawings. In addition, for installation components related to critical or precision parts of the cabinet, their dimensional accuracy also needs to be strictly in accordance with relevant requirements. Secondly, when connecting various components to each other, it is necessary to ensure the correct installation sequence and pay attention to the quality issues of the connecting rods to ensure the overall stability of the cabinet.

Once again, after the installation of the cabinet is completed, simple operation checks should be carried out, such as opening and closing the cabinet door to check whether the door opening angle is equal to or greater than 90 °; Is there any obvious shaking phenomenon during the opening or closing process of the door; Is there a lack of lubrication on the door shaft, causing harsh metal friction noise. After inspecting the hardware facilities and ensuring that there are no obvious quality issues, it is necessary to optimize the external brackets, connecting cables, and other components that may pose safety hazards, such as adding insulation covers, adding cable inlet and outlet ports, to ensure the safe operation of the switchgear.

Finally, after the above inspection is completed and it is confirmed that there are no quality or safety issues, clean the tools and debris inside the switchgear, and use cleaning tools to wipe the inner and outer surfaces of the switchgear clean, ensuring that there are no oil stains or dust.

2. Installation inspection of components inside the switchgear

The types and quantities of components inside the switchgear are quite complex, but overall, they are nothing more than protective components such as switches and circuit breakers. Therefore, when inspecting these components, it is important to pay attention to the following points: first, count the types and quantities of components to ensure that the materials are complete. Then, according to the specific requirements of the design drawings, compare the components to see if their models and quantities meet the standards. If the model is incorrect, it should be replaced in a timely manner, and if the quantity is insufficient, it should be supplemented in a timely manner. Secondly, strictly follow the relevant operating procedures for component installation to ensure that the installation position and method of the components meet the standards. At the same time, ensure that the wires connected to the components are as flat and straight as possible to avoid overlapping and crossing of the lines. Thirdly, it is necessary to reasonably arrange the spatial distance between components and between components and between components and cabinets, in order to prevent excessive distance and connection wire distance, which can increase the probability of line failure; Also, to prevent the distance from being too small and inconvenient to operate. Fourthly, after the installation of all components is completed, refer to the design drawings and confirm that there are no errors before conducting a power test to ensure the normal connection between each component. Fifth, do a good job of cleaning after installation. During the installation process of electronic components, there will be a large amount of residual wires, parts, and iron filings, some of which will adhere to the surface or inner layer of the components. Therefore, the cleaning work must be careful and careful to ensure that the details are clean.

3. Secondary wiring inspection inside the switchgear cabinet

Firstly, ensure that the identification of components and terminal circuit names is complete, correct, neat and aesthetically pleasing, and meets the requirements. Secondly, when connecting wires to components, it is necessary to follow the electrical equipment connection process requirements to ensure horizontal and vertical alignment, and to strive for beautiful wiring. Thirdly, the electrical clearance and creepage distance in the secondary circuit should comply with the process requirements of the secondary wiring construction. Fourthly, when the wire passes through metal partitions, busbars, instrument door wire fixing points, etc., the secondary wire should be protected. The length of the instrument door wire is moderate, ensuring that the door can open and close freely. Fifthly, select various copper connectors with sizes and specifications that comply with the wiring method of component terminals. Sixth, use crimping pliers to flatten the terminals of the copper connector, and then connect the terminals to the terminal posts. Pay attention to ensuring the correct connection method and the appropriate degree of crimping: prevent the crimping from being too tight, which may cause aging and fracture of the circuit in the later stage of use; Also, it is necessary to prevent loose crimping, which may cause the wire head and terminal to fall off in a short period of time, leading to a broken connection. Seventh, the length of the reserved wire should be moderate and the fixed position should be unified. Metal circular objects with a diameter of about 6mm can be used for grounding wires, N-wires, power wires, etc., and the wires can be wound 3-5 times; The secondary wiring should be constructed according to the drawings, with correct wiring that meets the requirements of the drawings, and the reserved positions for terminal wiring should be correct and uniform.

4. Installation inspection of switchgear mechanism

High voltage circuit breakers, low voltage drawers, and other moving contacts should be equipped with an appropriate amount of neutral lubricating grease; Circuit breakers and low-voltage drawers operate flexibly in and out without jamming. The installation of high and low pressure mechanisms, guide rails, etc. is correct and reliable. The grounding switch and opening operation are flexible, and the closing and opening markings indicate correctly; The grounding blade has neutral lubricating grease. The interlocking function of the high-voltage mechanism meets the requirements of "five prevention interlocking" (preventing accidental opening and closing of circuit breakers, preventing on load opening and closing of isolating switches, preventing live hanging of grounding wires, preventing circuit breakers with grounding wires, and preventing accidental entry into live intervals). The installation of the high-voltage cabinet valve mechanism is correct, the action is reliable, and there is no deviation in the lifting and lowering. The low-voltage closing and opening operating mechanism is installed correctly, fixed reliably, operates flexibly, and meets the interlocking requirements of the mechanism; The indication of the closing and opening marks is correct. There is an appropriate amount of neutral lubricating grease in the active parts of the institution. Handcarts, drawers, circuit breakers, etc. with the same functional unit should be reliably interchangeable.

5. Manufacturing and installation inspection of busbars inside switchgear cabinets

The phase sequence of the busbar is correct, and the installation operation is strictly carried out according to the drawing plan. At the same time, according to the actual installation needs, space for busbar connection can be reserved on the basis of the drawing standards, and the length of the busbar can be appropriately increased or shortened. Meet the requirements of the design drawings; The phase sequence identification of the busbar is pasted completely, correctly, neatly and aesthetically pleasing; The surface of the busbar should be kept as flat and crack free as possible, otherwise the busbar needs to be replaced; The connection holes, busbar sections, and cross-sections should be free of burrs, otherwise a small file needs to be used for grinding; The specifications of busbar connection bolts (screws), flat washers, springs, nuts, etc. are appropriate; The torque value of the fastening bolt meets the requirements, and the thread exposes 2-5 threads of the nut; After tightening the busbar connection bolts, there is a black fastening marking line on the bolts, and the marking line meets the requirements; The electrical clearance and creepage distance of the main busbar meet the requirements. The electrical clearance of the low-voltage cabinet shall not be less than 20mm, and the creepage distance shall not be less than 25mm; The high-voltage 6kV electrical gap shall not be less than 100mm, and the 10kV electrical gap shall not be less than 125mm; Installation of main busbar heat shrink tubing, with correct specifications, no damage, wrinkles, and neat cut sections; The busbar connection surface is flat, free of foreign objects, and the connection is natural and reliable; Require the connection surface to be brushed with conductive paste, which should be evenly applied. After the connection is completed, excess conductive paste should be wiped clean; A dedicated connector for connecting primary or secondary wires, with the correct direction and position of the connector.

6. Inspection of switchgear accessories

Instrument signs, drawer signs, eyebrow cabinet number plates, factory signs, simulation signs, etc. shall be complete, neat, beautiful, firm, and meet the requirements of the design drawings. If component model and specification identification, circuit identification, or phase sequence identification are required, the identification should be complete, neat, beautiful, and correct. The busbar frame, grounding bracket, cable bracket, insulator, etc. are installed correctly and firmly, and the arrangement and combination of the switchgear meet the requirements of the design drawings.

(Disclaimer: The article is sourced from the internet and does not represent the views or positions of our website. The copyright belongs to the original author and source. If there is any infringement or objection, please contact us for correction or deletion.)

（声明：文章来源于网络，不代表本站观点及立场，版权归原作者及原出处所有，若有侵权或异议请联系更正或删除。）