Comparison of the performance of sparsely screened and coaxial HV cables

It is rare for modern power cables to use a solid, continuous screen in their construction. For reasons of economy and ease of construction modern cables increasingly use screens comprised of sparsely spaced conductors. The electrical relationship between a screen manufactured using this construction and the core it surrounds is markedly different to the relationship between a solid coaxial screen and the core it surrounds. The ability of a cable screen to return current during a fault situation is significantly dependent on its relationship with the core carrying the fault energy and has significant impact on the performance of the earthing systems involved. This paper examines how different the performance of the sparsely screened cables is to their solidly screened predecessors.