Investigation on Steady-state Performance of 500 kV Single-core AC Submarine Cables under Different Grounding Methods

The investigation of grounding methods for long-distance AC submarine cables is of great importance for the safe operation of the cable system. This paper uses the multi-conductor analysis method to establish a computational model of a 500 kV AC submarine cable system with solid bonding grounding and multiple intermediate shorting point grounding. Subsequently, a matrix cascading algorithm is used to calculate and analyze the steady-state characteristics of the submarine cable system. The results show that the core current under the solid bonding method gradually decreases with the distance increase while the sheath current and armor current remain unchanged. Under the multiple intermediate short-circuit grounding method, the sheath-induced voltage significantly reduces, and the sheath current and armor current exhibit a jagged and staircase-like decrease, respectively.