texasheart.org Main Substation (MSS1) 13,800 volts Analogies: Chest Pain = Corona Minor Stroke = Tracking Cardiac Arrest = Arcing (may not be able to resuscitate electrical system) Building transformers 480 volts Circulatory System

Our electrical infrastructure Rust Bird caging Heat damage Damaged insulation ~50 yr. old conductor All pictures of actual conditions: July 2014

Items performed to date (no outage) Installed temporary power quality monitors –Main substation and key building substations Ultrasound testing –All substations Discovered arcing, tracking and corona Identified arcing in Basic Science Building & Med School –Replaced breakers Started Electrical Coordination Study Transformer Oil Sample Testing Removed LIB (temp. HVAC load) and ALTC (temp. load) Refurbished main and building substation breakers

Short Term (outage-6hr mid Sept) Open MSS1 and insulate wiring Hi pot MSS1 Replace oil in transformers

Recommendations ( Jan outage) Replace MSS1 –Main 13,800 volt substation is at its end-of-life. –MSS1 is the heart of the electrical system. It serves as a 13,800 volt “pump” for the entire Long Campus. –MSS1 was purchased, as a used item, from CPS Board (today known as CPS Energy) ~50 years ago. Replace oldest conductors –MED lines are the oldest. Rework all building substations transfer switches, breakers, bus bars. Perform another ultrasound test after outage is complete to compare against prior ultrasound test performed before the outage.