Judgment standard for sealing performance of waterproof joint

At present, the main evaluation standard of waterproof performance of waterproof connector is based on IP waterproof grade standard. According to the waterproof performance of the waterproof joint, it mainly depends on the following two digits of ipxx: XX, D, X is from 0 to 6, Z high-grade is 6; the second digit is from 0 to 8, Z high-grade is 8; so the Z high waterproof grade of the waterproof joint is IP68.

The molded cable accessories are mainly used in the straight through waterproof joints of 35 kV and above cross-linked cables. It is made of irradiated or chemically crosslinked polyethylene film tape wrapped around the treated cable joint, pressed by special mold (aluminum mold or heat-resistant tension belt) and heated to form the joint.

In the production process of irradiated cross-linked polyethylene strip, after pre stretching treatment (stretching at 100C for 30%, then cooling to cut coil), wrapping to form joint, heating to retract, the interlaminar air gap of the wrapped strip is compressed, so as to improve the air gap discharge voltage. The partial discharge level of this kind of joint is high, which is suitable for making cable joint with higher voltage level.