The article deals with the use of a tube-regulator (multifunctional element) as reinforcing insulation for 110 kV couplings, the operation of which is based on the use of heat-shrinkable tubes with special properties as elements that leveling the field. In this paper, we consider the key features of modeling the design of the tube-regulator and its optimization, made in the form of a combination of several heat-shrinkable tubes with specified parameters. Optimization of the design and analysis of its performance was carried out in a specialized software package ELCUT Professional. In the course of the work, a general optimal view of the structure and the parameters of each individual element of the tube-regulator were found. The most vulnerable zones were also found in which the electric field strength reaches the highest values. Recommendations are given on the arrangement of the structure to obtain the best possible picture of the distribution of the electric field in cable cutting.