A 13.8kV substation stepping down from a 69kV utility feed to serve an entire campus — the only project in this program engineered above 600V, sitting deliberately at the boundary between electrical engineering and power systems engineering.
The project brief: a 13.8kV distribution substation serving a large campus/industrial site — roughly 15 MVA of connected load — stepping down from a 69kV utility subtransmission feed through a main-tie-main pair of 15/20 MVA power transformers, feeding a campus-owned medium-voltage distribution loop that reaches a dozen unit substations. Every other project in this program lives entirely below 600V inside one building's service; this one is the utility connection point itself, engineered at medium voltage for an entire campus.
This module walks the whole project the way a campus/industrial electrical engineer actually needs it: how to read the substation's one-line diagram and main-tie-main topology, a worked power transformer sizing and short-circuit fault current calculation that drives breaker selection, the core protective relay functions (50/51, 87, 27/59) shown on the one-line, the IEEE 80 grounding grid concept behind step and touch voltage, and — explicitly — where this project's scope ends and a dedicated Power Systems Engineering program's scope begins. The full worked numbers and complete bill of materials are part of the unlocked module below.