Research on grounding performance of 500 kV AC submarine cable based on improved multi-conductor cell analysis method

• Published in: Dianji yu Kongzhi Xuebao = Electric Machines and Control Vol. 29; no. 6; p. 22
• Main Authors: Su, Ningjie, Ge, Junkai, Zhang, Jialin, Yang, Yong, Ye, Haoliang, Chen, Xiangrong
• Format: Journal Article
• Language: Chinese; English
• Published: Harbin Harbin University of Science and Technology 01.01.2025
• Subjects: Armor; Conductors; Electric currents; Electrical impedance; High voltages; Impedance matrix; Induced voltage; Permits; Series expansion; Sheaths; Submarine cables; Undersea cables; Voltage reduction
• ISSN: 1007-449X
• DOI: 10.15938/j.emc.2025.06.003

An improved multi-conductor cell analysis method was proposed to study the grounding performance of ultra-high voltage（UHV） submarine cable systems. First, the impedance matrix and shunt admittance matrix of the submarine cable were derived. Subsequently, the Laurent series expansion was introduced to solve the node admittance matrix of the multi-conductor segments of the submarine cable. Finally, a cascade algorithm for the node admittance matrix of the submarine cable under different grounding methods was established. The computational efficiency was significantly improved by this method compared to the traditional multi-conductor cell analysis method. A grounding performance study was carried out on a 500 kV AC submarine cable system. The results indicate that introducing intermediate shorting points（ISP） can significantly reduce the sheath induced voltage. The voltage reduction decreases as the number of ISPs increases, achieving a 93.84% decrease at 3 ISPs. The sheath current increases whereas the armor current decreases at ISP. With 1 ISP, the maximum sheath current increases by 4.26% and the maximum armor current decreases by 5.46%. The number of ISPs does not significantly affect the core current. A 6.34% reduction in total system power loss is achieved when the submarine cable system incorporates only one ISP. The results provide a new computational method and theoretical basis for the study of grounding performance in UHV AC submarine cable systems.