Effective 11/2003
Page 12
I.L. 66A7535H02
present, this jumper resides on the stationary side of the
switchgear assembly. The proper current sensor input is
required on the external sensor input terminals B-4, B-5 of
the breaker secondary contacts.
current sensors. Residual ground fault sensing features are
adaptable to main and feeder breaker applications.
2.3.3 Zero Sequence Sensing
Zero Sequence Sensing, also referred to as vectorial
summation
(See Figures 2.2, 2.2A and Appendix C)
, is
applicable to mains, feeders, and special schemes
involving zone protection. Two optional CH Type-V Zero
Sequence current sensors are available. The sensors have
a 5.25” I.D. (13.33cm) with a 7.4” O.D. (18.80cm). One
style is 69C3016G01 has a dual ampere rating with taps
for 100:1 and 200:1. The second style is 69C3016G02 has
an ampere rating of 50:1.
In this scheme, all breaker secondary currents (at the 100 mA level) are summed together at the PC
board donut transformer to sense ground fault via element R5.
Do not jumper secondary contacts B-6, B-7. This will defeat the residual ground fault protection.
2
1
Notes:
Source
R5
Digitrip 1150V
1
K2-8
Load
K1-4
K1-3
10:1
10:1 AUX. CT
K2-9
K1-5
K1-2
Black
Trip
Actuator
+
-
L
B
L
C
L
A
K1-6
K1-7
K1-8
K1-9
CSA1
A-4
A-19
CSA2
A-5
CSB1
A-20
CSB2
A-6
CSC1
A-21
CSC2
X1
X2
B-5
B-4
R/1
R/1
2.3.2 Residual Sensing
Residual is the standard operating mode of ground fault
sensing. This mode utilizes one current sensor on each
phase conductor
(See Figure 2.1)
. If the system neutral is
grounded, but no phase to neutral loads are used, the
Digitrip 1150V includes all of the components necessary
for ground fault protection. This mode of sensing vectorily
sums the outputs of the three or four individual CH Type-V
Figure 2.1 Breaker Using Residual GF Sensing
