SECTION 16362 - SERVICE ENTRANCE EQUIPMENT
CONSTRUCTION STANDARD
PART 1: GENERAL
This section of the design standard includes requirements for the service entrance
equipment for facilities at the University of Texas. This is a design standard and is not
intended to be used as guide or construction specifications.
PART 2: PRODUCTS
A.
Unit Substation:
1. The double-ended unit substation shall include two liquid (less-flammable)
filled transformers each capable of carrying the entire load. The transformers
will typically be connected delta-grounded wye. Two each, two and one half
percent (2-1/2%) taps FCAN and FCBN shall be included in the high voltage
winding. All windings shall be copper. The transformer shall carry its
continuous rating with average winding temperature rise by resistance not
exceeding 55 degrees Celsius. Accessories shall include a de-energized tap
changer externally operable with a padlockable handle, combination drain and
filter valve with sampling device, manual gas pressure test connection, filling
plug and filter press connection in cover, top liquid thermometer, magnetic
liquid level gauge, pressure vacuum gauge, removable handhole in cover, and
provisions for lifting and jacking.
B.
The circuit breakers protecting each transformer shall be air-magnetic with a 750
MVA symmetrical short circuit rating at 12 kV and a 250 MVA rating at 4.16 kV.
The breakers shall typically be rated at 1200 amperes continuous and have a BIL
rating of 95 kV at 12 kV and 60 kV at 4.16 kV. A control voltage of 120 VAC
shall be used for closing and a capacitive voltage-storing device shall be used for
tripping. Three overcurrent relays and one residually connected ground
overcurrent relay shall be used for fault protection. A voltmeter and an ammeter
shall be included with each breaker.
C.
The load interrupter switches shall be non-fused, three pole, manually operated,
with the switch action being quick-make, quick-break stored energy operator. The
switches shall be rated 600 amperes continuous with a 58 kA RMS asymmetrical
momentary (10 cycle) and fault close rating. The 12 kV switches shall have a BIL
of 95 kV and the 4.16 kV switches shall have a BIL of 60 kV. The load
interrupter switches shall contain the necessary number of potheads to terminate
either PILC or VCL cable.
END OF STANDARD 16362
Design & Construction Standards, Printed September 15, 1998
16362-1