REPRESENTATIVE MODELLING OF VERY LONG HVDC CABLES

Abstract

Developments in HVDC and cable technologies have opened the door for integration of remote renewables into established electricity systems to displace non-renewable generation. With a significant proportion of solar energy resource concentrated on the Australian and African continents, and load centres in Europe and the ASEAN regions, HVDC projects with cable connection lengths greater than 3000 km are under development. This paper develops a frequency dependent model (FDM) of the DC cable for the Sun Cable Australia-ASEAN Power Link (AAPowerLink). The effect of field joints and the associated earthing resistance is addressed. Exclusion of field joints introduces discrepancy in the core voltage along the cable length and the frequency dependent impedance. Simplification of the cable model within an electromagnetic transient (EMT) platform, whilst retaining a representative frequency dependent behaviour, is demonstrated. Modelling in PSCAD/EMTDC suggests minimum impact of submersion depth on the cable characteristics. Furthermore, the potential for harvesting energy at the field joints is explored.