Cable Sheath Loss Reduction Strategy Research Based on the Coupled Line Model

Power cables are playing an increasingly important role in the power grid. The sheath loss is one of the main shortcomings of the power cable which will cause thermal problems and limit the cable´s ampacity. We carry out a systematic research on the sheath loss of cables with different arrangements, including single bonding, solid bonding, and cross bonding. For cross-bonded cables, we study how the cross-bonding joints number and segment length deviation influence the sheath loss. To reduce the sheath loss, this paper studies a promising measure using connecting impedance in the cross-bonding joints, and the characteristic of the connecting impedance is fully revealed. The computer efficient algorithm is established to fulfill the loss calculation task, which is based on the improved coupled line model. The key of the coupled line model is to use series expansion to calculate the admittance matrix without diagonalizing the complex propagation matrix of the cable line. The dimension of the nodal equation is also greatly reduced.