Calculation of the Ampacity of HVDC Cables Considering the Limitation of Conductor Temperature and Insulation Layer Temperature Difference

High-voltage direct current transmission is a vital component of power transmission over long distances. It can be used to establish existing power lines and supply island power. HVDC cables' ampacity calculation is related to system stability. Based on the IEC standard, this paper improves the analytical calculation formula of the HVDC cable by considering both the temperature limit of the conductor and the temperature difference of the insulating layer at the same time. It demonstrates its validity, as well as its comparison and verification using finite element analysis. In this paper, the influence of outer wall temperature on HVDC cable ampacity calculation is studied. This provides a basis for engineers to calculate HVDC cable ampacity.