Introduction: Research and development work is required to limit the uncertainty and contribute to the review and update of National Grid documents that affect insulation coordination aspects of transmission substations. This work covers the overvoltage levels within a substation with regard to lightning and switching impulses.

Objectives:

To minimise costs associated with surge arrestors on the Transmission Network by optimised their location.

Expected Benefits:

• Review of existing practice of surge arresters and related insulation coordination

• Develop models for key scenarios of transients(Lightning and switching) in transmission substations

• Develop simple rules and techniques for optimising the use and location of surge arresters in substations

• Develop necessary background knowledge for overvoltage protection of transformer, GIS, and cable

• Investigate overvoltage protection special cases of transformer fault scenarios and GIS-Cable networks

• Obtain the EMTP simulation models of all above tasks and activities