You can access the IEC standards with one of the following links:
Join any of our WhatsApp groups named “Updates”: https://elec-engg.com/updates
download
Option 1: https://drive.google.com/drive/folders/19lPUREzUAdwL9CBZROwpUi9p3PZ-nipL?usp=sharing
Option 2: https://mega.nz/folder/5IMmxaTK#DlC52_gGmGxdg4pZsR20rg
List of IEC standards: https://en.wikipedia.org/wiki/List_of_IEC_standards

My Best To All,
Please include the IEC standars for Substation Design.
Thanks.