TM5-811-1/AFJMAN
32-1080
SECTION A-A
US Army Corps of Engineers
Figure 4-6. Main Electric Supply Switching Station, 35 kV Maximum.
Table 4-5. Primary Insulator Ratings by Class.
ter, varmeter, and watthour demand meter. Pro-
ANSI
vide strip-chart recorders if approved by the
NEMA
Nominal
TR
Class
Number
Voltage
HOST/REQ CMD.
115 kV
286; 288
52-3; 52-4
8; 9
(d) Phase and ground undercurrent relays.
69 kV
216; 286
52-3; 52-4
5; 6
A separate undercurrent relay shall be provided
214; 216
52-3; 52-4
46 kV
4; 5
for each phase and for ground fault detection.
group/gang operated, vacuum, sulfur hexafluoride
Directional overcurrent relays shall be used to
(SF,), or other dielectric as approved by the Host
detect short-circuit current flowing in a particular
Command coordinated with the Requiring Com-
direction. Directional power relays shall be used to
mand (HOST/REQ CMD).
detect power flow from Air Force generators into a
(b) Circuit breakers. Outdoor power type,
commercial system. Other relays, such as trans-
metal-clad, sheltered aisle type, vacuum or air
former differentials, should also be installed as
dielectric, group mounted, or individually mounted
required by sound engineering practices.
(2) Feeder sections. Metal-clad sheltered aisle
with vacuum, SF,, or other dielectric as approved
by the HOST/REQ CMD.
type, vacuum or air, dielectric, group mounting
4-15
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