Page 489 - Industrial Power Engineering and Applications Handbook

Instrument and control transformers: application and selection 15/463

jR

Y B Y

winding
-y
N'
& a- CV,=O
R"
Tertiary vTm
winding
Tertiary V
winding
v, = VT I
Secondary vs IC'

-
Y
Y
B
winding
Secondary
winding vs
1 R" I y" 1 8" 1
R"'
Figure 15.5(a) An RVT in a healthy system Figure 15.5(b) An RVT under ground fault on a 34 four-wire
grounded neutral system

= &vp

Tertiary
winding
V'3.VT
a' a"
1_ ve = 3vT c = 3v,
Secondary [ 11; 113 {3. vsF- - - - -3,
N'
1
I
I
€3"'
winding m
7
Figure 15.5(c) Ground fault on a
Y 3-44 three-wire delta or 34, four-
N \'3 vs wire ungrounded star system