A Method for Calculating Grounding Current of AC Submarine Cable Armor Based on Load Current

Submarine cable armor is connected to the earth to form a circuit,and load current of high-voltage AC cable core generates an induced voltage in submarine cable armor layer through electromagnetic induction.Induced voltage passes through the circuit to form armor grounding current.Armor grounding current has been applied in safe operation and current carrying capacity calculation of submarine cables.In the paper,a calculation model for grounding current of submarine cables was established,and an equation system for the circuit in model based on Kirchhoff’ s voltage law was wrote.Induced voltage of armor layer on the right side of the equation system could be linearly represented by load current of wire core according to electromagnetic induction law.By using Kramer’ s rule to calculate the solution of the equation system,armor grounding current was expressed linearly in a load current determinant composed of cable phase distance and structural parameters of the body.Actual operation case of Zhoushan-Ningbo 500 kV AC submarine cable showed that the method of calculating armor grounding current based on load current was simple,effective and feasible.