GE L90 Instruction Manual page 256

5.6 CONTROL ELEMENTS
EXAMPLE 2: BREAKER TRIP CIRCUIT INTEGRITY MONITORING
If it is required to monitor the trip circuit continuously, independent of the breaker position (open or closed), a method to
maintain the monitoring current flow through the trip circuit when the breaker is open must be provided (as shown in the fig-
ure below). This can be achieved by connecting a suitable resistor (see figure below) across the auxiliary contact in the trip
circuit. In this case, it is not required to supervise the monitoring circuit with the breaker position – the
selected to "Off". In this case, the settings will be:
# DIGITAL ELEMENT
#
5
UR Relay - Form-A
I = Current Monitor
V = Voltage Monitor
827074A1.vsd
5-166
1 DIGITAL ELEMENT
FUNCTION: Enabled
DIG ELEM
MESSAGE
Bkr Trip Cct Out
DIG ELEM
MESSAGE
Cont Op 1 VOff
DIG ELEM
MESSAGE
DELAY:
DIG ELEM
MESSAGE
DELAY:
DIG ELEM
MESSAGE
Off
DIGITAL ELEMENT
MESSAGE
TARGET: Self-reset
DIGITAL ELEMENT
MESSAGE
EVENTS: Enabled
DC+
H1a
I
H1b
V
H1c
52a
R
Trip
Coil
DC–
Figure 5–101: TRIP CIRCUIT EXAMPLE 2
L90 Line Differential Relay
1
1 NAME:
1 INPUT:
1 PICKUP
0.200 s
1 RESET
0.100 s
1 BLOCK:
1
1
Table 5–19: VALUES OF RESISTOR 'R'
POWER
SUPPLY (V DC)
24
30
48
110
By-pass
125
Resistor
250
5 SETTINGS
setting is
BLOCK
RESISTANCE POWER
(OHMS) (WATTS)
1000 2
5000 2
10000 2
25000 5
25000 5
50000 5
GE Multilin