Fault Current Distribution in New Type of EHV cables
National Grid Electricity System Operator
National Grid TO Innovation Team
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Innovation Funding Incentive
Although Oil filled cables have well-established IGR and cable factors are set out in ER S34 (A guide for Assessing the Rise of Earth Potential at Substation Sites), XLPE cables have had no such study conducted on them. It is vital to understand the electrical properties of the cable sheath in returning some of the earth fault current as this is a key factor in the Ground Current Return (IGR). In order to analyse new types of XLPE cables, it is necessary to calculate cable parameters to a high degree of accuracy by software packages, numerical methods and formulae. This allows the effect of important variables upon IGR to be calculated. At present time specialist contractors are utilised to calculate the IGR for any cable run. This project aims to codify this knowledge and integrate this into Digslient so IGR for faults can be calculated as a standard procedure.
To derive and calculated the IGR for faults on XLPE cable. These derivations can then be utilised to calculate cable factor for different XLPE cable. These cable factors are then to be integrated into Digslient to enable fault current calculations to be carried out semi autonomously.