Causes of conductor shielding defects in cross-linked power cables

Rated voltage 3.6kV and above cross-linked polyethylene insulated power cables (referred to as cross-linked power cables) shall have conductor shielding and insulation shielding. Conductor shielding is mainly to ease the cable internal and electric field stress concentration, eliminate the effect of conductor stranding, improve the cable internal electric field and radial distribution to improve the electrical strength of the cable. Cross-linked power cables in the production process due to the influence of various factors, the conductor shielding depression, raised and other defects, resulting in uneven distribution of the internal electric field, seriously affecting the cable's electrical performance and service life. 1. conductor shielding defects in the types and causes, cross-linked power cables in the production process of conductor shielding defects are mainly the following: depression: conductor shielding depression mainly due to the conductor's most The gap between the outer single line is too large. Due to the cross-linked power cable conductor for the tightly stranded conductor, conductor shielding extrusion using extrusion molds, into the cross-linking pipeline and in a high temperature and high pressure environment, if the conductor structure is unreasonable or not enough tightening, it is inevitable that the conductor shielding depression. Tightly pressed conductor in the process of releasing the outer layer of loose strands, conductor in the melt welding head improperly handled will also appear in the outer layer of loose strands, which also leads to the cause of conductor shielding depression. Bump: In order to ensure that the electric field inside the power cable is uniform, the conductor shielding surface is required to be smooth. If the shielding material in the extrusion process temperature control is out of order, resulting in pre-crosslinking of the shielding material, the formation of raised particles on the surface of the extruded layer. These raised particles in the power cable in the long-term implementation of the process is prone to discharge, and then in the insulation to form an electric tree " and ultimately lead to power cable breakdown.2. Conductor shielding defects check: high-voltage crosslinked power cable insulation layer is thicker, and at the same time there is insulation shielding, so the conductor shielding for the surface of the good check is more difficult. The following methods can be used to check the conductor shielding. Methods: take the insulation core sample length 1m, one end of the insulation shield to retain 20cm long, insulation shielding stripped, try not to damage the insulation, and then put it into the silicone oil box heating, silicone oil temperature of 120 degrees Celsius, placed in 3h after the insulation becomes transparent, and then use a strong light source on the conductor shielding the surface of the condition of the inspection.-3、About Evergrande Electronic Products Network platform related to the introduction and sales of products briefly: Evergrande Electronic Products Network - a professional agent / production / sales of a variety of {connectors | wiring harness | wire and cable products }; if you have a related [connectors | wiring harness | wire and cable products] purchasing / sourcing needs or would like to buy / to understand what connectors | harness | wire and cable products we can provide solutions, please contact the following Division I business personnel; If you have related [connectors | wire harness | wire and cable products] sales / resources and promotion needs, please click on the "¡¡ Business Cooperation ←" with the person to discuss!