The report covers the detailed modelling of cable and overhead line components. Particular attention is paid to cable models appropriate for distribution networks, as this is was the initial objective of the project and literature on modelling of cables is not as widespread as that for other items of equipment.

Objectives

This project is being managed by the ENA on behalf of the ENA R&D Group.

This proposal was generated in direct response to the difficulties encountered by a number of DNOs when asked to provide long distance 33kV and 11kV connections to loads that had a potential to generate considerable harmonics. Concern was expressed about the possible planning implications and when the DNOs attempted to undertake system studies, it highlighted a real gap in the available understanding of the possible effects. The project will carry out system modelling with the aim of creating guidance to assist DNOs when faced with difficult planning decisions. The objective is to provide basic limits for current designs in terms of cables lengths/ types/ harmonic levels to supplement G5/4 (2001) and help reduce and simplify modelling requirements for relatively small capacity 33kV and 11kV connections.

The project has the following objectives:

• Review of existing standards on harmonic modelling

• Review of underground existing cable numerical models

• Establish a range of typical network scenarios for 11kV and 33kV networks and aims to categorise the different types of connections based on harmonic resonance considerations.