GE Power Management
750/760 Feeder Management Relay
12-
49
12 S5 PROTECTION
12.7 VOLTAGE
12
12.7 VOLTAGE
12.7.1 DESCRIPTION
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 und-
ervoltage protection feature 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 operating 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 overfre-
quency, 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 trans-
fer a load from its normal source to a standby or emergency power source.
12.7.2 BUS UNDERVOLTAGE
Bus undervoltage 1 & 2 are identical elements that generate outputs in response to undervoltage conditions on
the bus voltage inputs. The time delay characteristic can be programmed as definite time or inverse time. A
minimum operating voltage level is programmable to prevent undesired operation before voltage becomes
available. The setpoints for Undervoltage 1 are shown below; Undervoltage 2 setpoints are identical.
■
BUS UNDERVOLTAGE 1
■
[ENTER] for more
The Bus Undervoltage 1 setpoints path is:
\ SETPOINTS \ S5 PROTECTION \ VOLTAGE \ BUS UNDERVOLTAGE 1
BUS UNDERVOLTAGE 1
FUNCTION: Disabled
Range: Disabled, Trip, Alarm, Latched Alarm, Control
Select the required function.
BUS UNDERVOLTAGE 1
RELAYS (3-7): -----
Range: Any Combination of the 3-7 AUXILIARY Relays
Select the output relays required.
BUS UNDERVOLTAGE 1
PICKUP: 0.75 x VT
Range: 0.00 to 1.25 in steps of 0.01 x VT
Selects the pickup as a fraction of the nominal bus VT Secondary Voltage. For
example, if the nominal VT secondary voltage is 120 V, and an alarm is
required whenever the voltage goes below 110 V, enter (110/120) =
0.92 x VT
for the pickup.
BUS UNDERVOLTAGE 1
CURVE: Definite Time
Range: Definite Time, Inverse Time
Selects the shape of the undervoltage time curve to be used.
Definite Time:
Time delay equal to the
BUS UNDERVOLTAGE 1 DELAY
setpoint.
Inverse Time:
See Section 12.1.4: IAC CURVES on page 12–4.
BUS UNDERVOLTAGE 1
DELAY:
2.0 s
Range: 0.0 to 6000.0 in steps of 0.1 s
Selects the minimum operating time of Bus Undervoltage 1.
PHASES REQUIRED FOR
OPERATION: All Three
Range: Any One, Any Two, All Three
Select the type of operation required.
MINIMUM OPERATING
VOLTAGE: 0.30 x VT
Range: 0.00 to 1.25 in steps of 0.01 x VT
Inhibits the Bus Undervoltage 1 element for voltages below this level. Setting
to
0.00 x VT
will allow a dead bus to be considered a fault condition.
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Страница 144: ...10 14 750 760 Feeder Management Relay GE Power Management 10 10 MISCELLANEOUS FUNCTIONS 10 S3 LOGIC INPUTS 10 ...
Страница 152: ...11 8 750 760 Feeder Management Relay GE Power Management 11 3 OUTPUT RELAYS 3 7 AUXILIARY 11 S4 OUTPUT RELAYS 11 ...
Страница 216: ...12 64 750 760 Feeder Management Relay GE Power Management 12 9 BREAKER FAILURE 12 S5 PROTECTION 12 ...
Страница 484: ...17 78 750 760 Feeder Management Relay GE Power Management 17 10 PLACING THE RELAY IN SERVICE 17 COMMISSIONING 17 ...
Страница 488: ...A 4 750 760 Feeder Management Relay GE Power Management A 1 FIGURES AND TABLES APPENDIXA A ...
Страница 490: ...B 2 750 760 Feeder Management Relay GE Power Management B 1 EU DECLARATION OF CONFORMITY APPENDIXB B ...
Страница 492: ...C 2 750 760 Feeder Management Relay GE Power Management C 1 WARRANTY INFORMATION APPENDIXC C ...
Страница 502: ...x 750 760 Feeder Management Relay GE Power Management INDEX ...
Страница 503: ...GE Power Management 750 760 Feeder Management Relay NOTES ...