Calculation Method of Circulating Current of Double T-type Metal Sheath Based on Distributed Parameters of Cable

In urban power supply, the proportion of cable lines is increasing. With the improvement of cable voltage grade and transmission capacity, the shield ring current induced by the core wire increases, and the excessive shield current seriously affects the safe operation of the cable. Based on the existing equivalent calculation model of cable shield ring current, this paper analyzes the existing model problems in theory and proposes a new distributed equivalent circuit model. It gives the formula for shield current calculation and verifies the correctness of the proposed model through simulation.