The IEEE Red Book is good. (ANSI- IEEE Standard 141 "Recommended Practice for Power Distribution in Industrial Plants".
Check Cutler-Hammer's Consulting Engineering Handbook available on line. The first chapter is a great synopsis of electrical design.
Go to manufacturer?s websites to download white papers or catalog data on medium voltage switchgear and equipment.
What is "Buff" book anyway?
IEEE Std 242 - "Protection and Coordination"