I. Overview 

High-voltage (6-35KV) porcelain wall bushing (hereinafter referred to as bushing) is suitable for power frequency AC rated voltage 35KV and below in power stations and substations, for conductors (busbars) to pass through grounding partitions, walls and It is used for insulation support and connection with external conductors (busbars) in the enclosed power distribution structure. There are three types of bushings with aluminum conductor, copper conductor and without conductor (bus type).

   The casing pipe is divided into indoor and outdoor-indoor series according to the installation location, and is divided into four levels of 6, 10, 20 and 35kV according to the rated voltage.

   Model description of casing:

   CL──Indoor aluminum conductor through wall bushing;

   C──Indoor copper conductor through wall bushing;

   CWL──Outdoor—Indoor aluminum conductor through-wall bushing;

   CWWL──Fouling-resistant outdoor-indoor aluminum conductor through-wall bushing;

   CW──Outdoor—Indoor copper conductor through wall bushing; (plus B): reinforced type

   CWW──Pollution-resistant outdoor-indoor copper conductor through-wall bushing;

   CM──Indoor bus-type through-wall bushing;

   CMWW──Fouling-resistant outdoor-indoor bus-type wall bushing;

   The number after the letter is the design sequence number.

   For bushings with conductors, the fraction after the dash, the numerator is the rated voltage of the bushing in kilovolts; the denominator is the rated current ampere of the bushing; the number after the second dash is the pollution level number (for example: CWWL-20/3000A-3) .

   For busbar bushings, the number after the first dash after the letter is the rated voltage in kilovolts; the number after the second dash is the diameter of the inner hole of the bushing porcelain sleeve in millimeters; the number after the third dash is the pollution level number (such as : CMWW-20-180-3).

2. Introduction to the structure

    6-35kV wall bushing adopts porcelain insulation structure. The bushing is composed of three parts: porcelain tube, grounding flange and conductor (for bushing with conductor). The conductor of the busbar bushing shall be prepared by the user. The surface of the porcelain tube is brown, red and white, and the aluminum alloy accessories are coated with a protective layer to prevent corrosion.

   The porcelain tube and grounding flange of the casing adopt a pressed structure, which has a certain degree of airtightness. 20kV and 35kV grade casing silicone rubber inner hole and 35kV grade casing insulator fix the middle flange part, the conductor is fixed with the contact shrapnel, and it is in good contact with the pressure equalizing layer of the porcelain tube inner hole, which improves the discharge voltage and the gliding discharge voltage .

3.technical data

   The casing should meet the following standards:

   GB12944.1──91 "Technical Conditions for High-Voltage Wall Porcelain Sleeve";

   GB12944.2──92 "Dimensions and Characteristics of High-Voltage Wall Porcelain Sleeve";

   GB5273──85 "Terminals for transformers, high-voltage electrical appliances and bushings".

4.use and maintenance

1. Conditions of use

The ambient temperature is -10℃ to +50℃ and the altitude does not exceed 3000 meters. The relative temperature of the casing for indoor installation does not exceed 80%.

When the ambient temperature exceeds +50℃, the use of the bushing is specified in Appendix A of GB4109. The heating of each part of the tube with conductor during long-term operation shall not exceed the regulations in Table 4.

2. Casing installation

(1) During installation, the main part of the middle flange of the casing (that is, the part shown in dimension d in the figure) should be extended into the wall hole in the outdoor casing, which should be passed from the outdoors to the indoors.

(2) When the horizontal angle of the wall-through pipe flange installation face is on one side of the wall outdoor, it is recommended to be about 2, and it can also be 0 degrees in special circumstances.

3. Installation diagram

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