Stator Differential (Ansi 87S) - GE G60 Instruction Manual

CHAPTER 5: SETTINGS

5.7.5 Stator differential (ANSI 87S)

SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  STATOR DIFFERENTIAL
 STATOR
 DIFFERENTIAL
The stator differential protection element is intended for use on the stator windings of rotating machinery.
This element has a dual slope characteristic. The main purpose of the percent-slope characteristic is to prevent a
maloperation caused by unbalances between CTs during external faults. CT unbalances arise as a result of the following
factors:
• CT accuracy errors
• CT saturation
G60 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
STATOR DIFF

FUNCTION: Disabled
STATOR DIFF LINE

END SOURCE: SRC 1
STATOR DIFF NEUTRAL

END SOURCE: SRC 1
STATOR DIFF

PICKUP: 0.100 pu
STATOR DIFF

SLOPE 1: 10 %
STATOR DIFF

BREAK 1: 1.15 pu
STATOR DIFF

SLOPE 2: 80 %
STATOR DIFF

BREAK 2: 8.00 pu
STATOR DIFF

BLK: Off
STATOR DIFF

TARGET: Self-reset
STATOR DIFF

EVENTS: Disabled
Figure 5-126: Stator differential characteristic
GROUPED ELEMENTS
Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4
Range: SRC 1, SRC 2, SRC 3, SRC 4
Range: 0.050 to 1.000 pu in steps of 0.001
Range: 1 to 100% in steps of 1
Range: 1.00 to 1.50 pu in steps of 0.01
Range: 1 to 100% in steps of 1
Range: 1.50 to 30.00 pu in steps of 0.01
Range: FlexLogic operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
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