5-72 750/760 Feeder Management Relay GE Multilin
5.6 S5 PROTECTION 5 SETPOINTS
5
5.6.10 REVERSE POWER (IF ENABLED)
PATH: SETPOINTS ÖØ S5 PROTECTION ÖØ REV PWR
A Reverse Power element is generally associated with generator protection. Such an element is used to detect loss of
mechanical power coming into the turbine and to trip the unit to prevent turbine blade heating or other adverse effects in
turbo-generator sets. The
REV PWR PICKUP setting is usually set as low as the relay can measure, but no higher than one-
half the electrical power required to motor the generator with total loss of mechanical power. The Reverse Power element is
not normally used in conventional feeder protection applications.
The Reverse Power element generates an output when the three-phase reverse real power is greater than the REV PWR
PICKUP setting. It is recommended to set REV PWR DELAY to 1 second or higher to avoid problems with power oscillations
that may be experienced on synchronization; a setting in the range of 10 to 15 seconds is typical. Recall that the rated
power is calculated as follows:
(EQ 5.18)
The sensitivity of this element and the requirement to have two times pickup limits its range of application. The
motoring power cannot be less that 3% of rated, and the angle away from the 180° angle of maximum sensitivity
should not be greater than ±85 to 87° due to reactive loading on the generator.
This element is optional and available from GE Multilin as Mod 008. To order, please contact the factory with the serial num-
ber of the 750/760 relay. Refer to Appendix A.1.1: Reverse Power on page A–1 for the complete procedure for installing
and verifying the Reverse Power element.
Figure 5–35: REVERSE POWER LOGIC
îš„ REV PWR
îš„ [ENTER] for more
REV PWR
FUNCTION: Disabled
Range: Disabled, Trip, Alarm, Control
REV PWR
RELAYS (3-7): -----
Range: Any combination of 3 to 7 Auxiliary relays
See 5.6.1: Overview on page 5–32 for details.
REV PWR
PICKUP: 0.050 xRATED
Range: 0.015 to 0.600 x RATED in steps of 0.001
REV PWR
DELAY: 10.0 s
Range: 0.0 to 6000.0 s in steps of 0.1
ENTER
ESCAPE
ð
ð
MESSAGE
ESCAPE
MESSAGE
ESCAPE
MESSAGE
ESCAPE
Rated Power 3 V
sec(line-line)
× VT Ratio I
sec(rated)
CT Ratio×××=
NOTE
Courtesy of NationalSwitchgear.com
To Next Page
Loading...
Need help?
General
