Study on the Effect of Multi-circuit Laying on Ampacity of Low Smoke Halogen-free Cable

In order to save cable laying space and improve operation transmission efficiency, multi-circuit cable laying methods are becoming more and more extensive. The interaction between multi-circuit cables also has an increasing impact on the current carrying capacity of the cable. Therefore, taking WDZ-YJY3×16 cable as an example, an electromagnetic-thermal coupling multi-loop simulation model is established and finite element simulation calculation is carried out. Firstly, through the established model, the cable temperature field under different circuit laying methods is compared, and the reasons affecting the change of cable current carrying capacity are analyzed. Secondly, by changing the spacing between multi-loop cables, the change law of cable current carrying capacity is analyzed, and the reasonable laying spacing of cables is obtained; Finally, the multi-circuit laying experiment of the design cable verifies the above simulation calculation results. The results show that the reasons for the change of the current carrying capacity of multi-circuit cables are not only from the mutual inductance between cables, but also related to the loss of the cable metal sheath and the temperature change of the cable. And WDZ-YJY3×16 cable reasonable laying spacing should be greater than 550mm, in the actual cable engineering application, should also be combined with the laying space comprehensive consideration, select the appropriate cable laying spacing, in order to ensure the cable can be safe and effective operation under the premise of increasing the ampacity. The research results have good reference significance for cable route planning, design and operation and maintenance.