GE 350-A9, Instruction Manual

Page: 231 / 334

CHAPTER 6: SETPOINTS S3 PROTECTION
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL 6–101
NOTE
NOTE:
The element drops out if the magnitude of the positive-sequence current becomes
virtually zero, that is, it drops below 0.02 x CT. Such a condition is taken as an indication
that the protected equipment is disconnected.
The following path is available using the keypad. For instructions on how to use the
keypad, please refer to
Chapter 3 - Working with the Keypad .
PATH :
SETPOINTS > S3 PROTECTION > SETPOINT GROUP 1(2) > DIRECTIONAL POWER
FUNCTION
Range: Disabled, Alarm, Latched Alarm, Trip, Control
Default: Disabled
For details see Common setpoints .
RCA
Range: 0 to 359° in steps of 1°
Default: 0°
This setting specifies the Relay Characteristic Angle (RCA) for the Directional Power
function. Application of this setting is threefold:
• It allows the element to respond to active or reactive power in any direction (active
overpower/underpower, etc.).
• It allows compensation for any CT and VT angular errors to permit more precise
settings.
• It allows for the required direction in situations when the voltage signal is taken from
behind a delta-wye connected power transformer and phase angle compensation is
required.
For example, the active overpower characteristic is achieved by setting RCA to "0°,"
reactive overpower by setting RCA to "90°," active underpower by setting RCA to "180°,"
and reactive underpower by setting RCA to "270°".
SMIN
Range: -1.200 to 1.200 x Rated Power in steps of 0.001 x Rated Power
Default: 0.100 x Rated Power
The setting specifies the minimum power as defined along the relay characteristic angle
(RCA) for the stage 1 of the element. The positive values imply a shift towards the
operate region along the RCA line; the negative values imply a shift towards the restrain
region along the RCA line. Refer to the Directional power sample applications of the
directional power element figure above for details. Together with the RCA, this setting
enables a wide range of operating characteristics.
The setting is a multiple of rated power where:
When VT CONNECTION = Wye,
Rated Power= 3 x VT SECONDARY x VT RATIO x PHASE CT PRIMARY
When VT CONNECTION = Delta,
Rated Power = sqrt(3) x VT SECONDARY x VT RATIO x PHASE CT PRIMARY
PICKUP DELAY
Range: 0.0 to 600.0 s in steps of 0.1 s
Default: 0.50 s
This setting specifies the time delay for this function to operate after pickup.
OUTPUT RELAY X
For details see Common setpoints .
BLOCK 1/2/3
For details see Common setpoints .