GE Feeder Management Relay 750 User Manual

GE Multilin 750/760 Feeder Management Relay 5-63
5 SETPOINTS 5.6 S5 PROTECTION
5
5.6.7 VOLTAGE
a) MAIN MENU
PATH: SETPOINTS ÖØ S5 PROTECTION ÖØ VOLTAGE
There are four undervoltage protection elements which can be used for a variety of applications:
• Undervoltage Protection: For voltage sensitive loads, such as induction motors, a drop in voltage will result in an
increase in the drawn current, which may cause dangerous overheating in the motor. The undervoltage protection fea-
ture can be used to either cause a trip or generate an alarm when the voltage drops below a specified voltage setting
for a specified time delay.
• Permissive Functions: The undervoltage feature may be used to block the functioning of external devices by operat-
ing an output relay, when the voltage falls below the specified voltage setting. Note that all internal features that are
inhibited by an undervoltage condition, such as underfrequency and overfrequency, have their own inhibit functions
independent of the undervoltage protection features.
• Source Transfer Schemes: In the event of an undervoltage, a transfer signal may be generated to transfer a load
from its normal source to a standby or emergency power source.
The undervoltage elements can be programmed to have an inverse time delay characteristic. The undervoltage delay set-
point defines a family of curves as shown below:
Figure 5–27: INVERSE TIME UNDERVOLTAGE CURVES
 SENSTV GND CURRENT
 [ENTER] for more
 BUS UNDERVOLTAGE 1
 [ENTER] for more
See page 5–64.
 BUS UNDERVOLTAGE 2
 [ENTER] for more
 LINE UNDERVOLTAGE 3
 [ENTER] for more
See page 5–65.
 LINE UNDERVOLTAGE 4
 [ENTER] for more
 OVERVOLTAGE 1
 [ENTER] for more
See page 5–66.
 OVERVOLTAGE 2
 [ENTER] for more
 NTR DISPLACEMENT
 [ENTER] for more
See page 5–67.
The operating time is given by:
(EQ 5.17)
where: T = Operating Time
D = Undervoltage Delay setpoint
V = Voltage as a fraction of the nominal VT
Secondary Voltage
V
pu
= Pickup Level
At 0% of pickup, the operating time equals
the Undervoltage Delay setpoint.
ENTER
ESCAPE
ð
ð
MESSAGE
ESCAPE
MESSAGE
ESCAPE
MESSAGE
ESCAPE
MESSAGE
ESCAPE
MESSAGE
ESCAPE
MESSAGE
ESCAPE
T
D
1 VV
pu
⁄–
--------------------------=
NOTE
D=5.02.01.0
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
20.0
0102030405060708090100110
% of V pickup
Time (seconds)
Courtesy of NationalSwitchgear.com

GE Feeder Management Relay 750 Specifications

General

Brand	GE
Model	Feeder Management Relay 750
Category	Protection Device
Language	English