Transient modeling and sensitivity analysis of cable system parameters

Traditionally, Extra High Voltage (EHV) transmission systems consist exclusively of Overhead lines (OHL) but in the recent years the utilization of High Voltage AC (HVAC) underground power cables (UGC) is increasing due to environmental, political and operational aspects. The application of EHV cables will influence the operation of the transmission system in both steady and transient state. Therefore, formulation of accurate cable simulation models is of great importance in order to understand the new phenomena introduced. This paper presents a comparison between two cable models, a detailed and a more simplified one, as well as a sensitivity analysis on several cable parameters. In this way, guidelines can be extracted concerning the parameters that have larger impact on the cable response and must be modeled in detail and the ones where simplifications can be made for achieving better computational speed. The simulations are performed using software package PSCAD/EMTDC.

I. Introduction

Recently, the Dutch transmission system operator, TenneT, extended the 380 kV grid with a new connection where underground power cables are integrated in order to guarantee sufficient electric power capacity for the densely populated Randstad region. Due to the limited experience in the Netherlands with underground power cables at 380 kV level, the Dutch TSO decided to research switching operations in HVAC cables, in order to identify possible undesired overvoltages and resonance phenomena. In order to study this kind of phenomena accurate simulation models should be built in software packages suitable for transient studies where the chosen modeling detail and parameters of the cable is of the utmost importance.