GE 750 User Manual

12-
60
750/760 Feeder Management Relay GE Power Management
12.8 FREQUENCY 12 S5 PROTECTION
12
12.8.3 FREQUENCY DECAY
There is one frequency decay protection element, ANSI device 81D which can provide a faster response to
system disturbances than the underfrequency elements. The setpoints for the Frequency Decay element are
as follows.
■ FREQUENCY DECAY
■ [ENTER] for more
The Frequency Decay setpoints path is:
\ SETPOINTS \ S5 PROTECTION \ FREQUENCY \ FREQUENCY DECAY
FREQUENCY DECAY
FUNCTION: Disabled
Range: Disabled, Trip, Alarm, Latched Alarm, Control
Select the required function.
FREQUENCY DECAY
RELAYS (3-7): -----
Range: Any Combination of the 3-7 AUXILIARY Relays
Select the output relays required.
FREQUENCY DECAY
RATE: 1.0 Hz/s
Range: 0.1 to 5.0 in steps of 0.1 Hz/s
Enter the rate of frequency decay above which the element will operate.
FREQUENCY DECAY
PICKUP: 59.00 Hz
Range: 20.00 to 65.00 in steps of 0.01 Hz
Enter the frequency level below which the frequency decay element will oper-
ate.
FREQUENCY DECAY
DELAY: 2.00 s
Range: 0.00 to 600.00 in steps of 0.01 s
Select the delay required.
MINIMUM OPERATING
VOLTAGE: 0.70 x VT
Range: 0.00 to 1.25 in steps of 0.01 x VT
Enter the minimum voltage required to allow the frequency decay element to
operate. Used to prevent incorrect operation before energization of the source
to the relay location, and during voltage dips.
MINIMUM OPERATING
CURRENT: 0.20 x CT
Range: 0.00 to 20.00 in steps of 0.01 x CT
Enter the minimum value of current required on any phase to allow the fre-
quency decay element to operate. Used to prevent underfrequency tripping
during periods of light load, when this action would have an insignificant effect
on the system.

GE 750 Specifications

General

Brand	GE
Model	750
Category	Relays
Language	English