Cable waterproof structure type:
For XLPE ACWU90 AC90 Cable, there are usually the following waterproof structures:
1. For single-core cables, wrap a semiconducting resistance hose on the insulation shield of the cable, wrap a common water blocking tape outside the metal shield, and then squeeze the outer sheath. The outer sheath material can be ordinary For PVC, HDPE material with radial water blocking function can also be used, depending on other performance requirements of the cable. For three-core cables, in order to ensure the full contact of the metal shield, only the single-conductance resistance hose is wrapped outside the insulating shield, and the water blocking tape is no longer wrapped outside the metal shield. Water blocking filling, inner lining and outer sheath materials are the same as those described in single-core cables.
2. The aluminum-plastic composite tape layer is longitudinally wrapped inside the outer sheath or inner lining layer as a waterproof layer.
3. Squeeze the HDPE outer sheath directly on the outside of the cable.
Cable waterproof structure type:
For XLPE insulated power cables, there are usually the following waterproof structures:
1. For single-core cables, wrap a semiconducting resistance hose on the insulation shield of the cable, wrap a common water blocking tape outside the metal shield, and then squeeze the outer sheath. The outer sheath material can be ordinary For PVC, HDPE material with radial water blocking function can also be used, depending on other performance requirements of the cable. For three-core cables, in order to ensure the full contact of the metal shield, only the single-conductance resistance hose is wrapped outside the insulating shield, and the water blocking tape is no longer wrapped outside the metal shield. Water blocking filling, inner lining and outer sheath materials are the same as those described in single-core cables.
2. The aluminum-plastic composite tape layer is longitudinally wrapped inside the outer sheath or inner lining layer as a waterproof layer.
3. Squeeze the HDPE outer sheath directly on the outside of the cable.
For PVC XLPE Insulated Power Cable, the metal sheath is mainly used to make the cable meet the waterproof requirements. The most important feature of the metal sheath is that it is completely impermeable, so the cable with the metal sheath has very good radial water blocking performance. The main types of metal sheaths are: hot-pressed aluminum sleeve, hot-pressed lead sleeve, welded corrugated aluminum sleeve, welded corrugated steel sleeve, and cold drawn metal sleeve.
Cable waterproof form:
Cable waterproofing methods are generally divided into longitudinal water blocking and radial water resistance. Water blocking yarn, water blocking powder and water blocking tape are commonly used in longitudinal water blocking. Their water blocking mechanism is that these materials contain a material that can swell in contact with water. When water flows from the cable end or from the sheath After entering the defect, this material will quickly expand with water to prevent further diffusion of water along the longitudinal direction of the cable, thus achieving the purpose of longitudinal waterproofing of the cable. Radial water resistance is mainly achieved by extruding HDPE non-metallic sheath or hot pressing, welding, and cold drawing metal sheath.
Cable waterproof test basis:
The cable waterproof test method, the cable longitudinal water resistance performance can be tested and judged by the IEC 60502-1997 ANNEX D (normative) or GB/T 12706.2-2002 Appendix D (standard catalog) water permeability test; and the cable radial water resistance Performance, currently is mainly determined by indirect methods, such as checking whether the HDPE non-metal sheath or non-metal sheath is defective. If these sheaths are determined to be intact, then the cable is considered to have good radial water resistance. performance. However, many users of this method have raised some questions, caused some disputes, and lacked convincing power. Therefore, cable manufacturers and users now urgently need a test method to determine the radial water blocking performance of the cable. This can avoid disputes between manufacturers and users about the cable’s radial water blocking performance due to the lack of a radial water blocking test method.