GE T60 Instruction Manual page 479

CHAPTER 5: SETTINGS
5.7.6.3 Instantaneous differential (ANSI 50/87)
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  TRANSFORMER  INSTANTANEOUS DIFFERENTIAL
 INSTANTANEOUS
 DIFFERENTIAL
The instantaneous differential element acts as an instantaneous overcurrent element responding to the measured
differential current magnitude (filtered fundamental frequency component) and applying a user-selectable pickup
threshold. Set the pickup threshold greater than the maximum spurious differential current that can be encountered under
non-internal fault conditions (typically magnetizing inrush current or an external fault with extremely severe CT saturation).
5.7.6.4 Hottest-spot temperature
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  TRANSFORMER  HOTTEST-SPOT TEMPERATURE
 HOTTEST-SPOT
 TEMPERATURE
The Hottest-Spot Temperature element provides a mechanism to detect abnormal winding hottest-spot temperatures
inside the transformer. It can be set to alarm or trip in cases where the computed hottest-spot temperature is above the
pickup threshold for a user-specified time (considered as transformer overheating).
T60 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
INST DIFFERENTIAL

FUNCTION: Disabled
INST DIFFERENTIAL

PICKUP: 8.000 pu
INST DIFF BLOCK:

Off
INST DIFFERENTIAL

TARGET: Self-reset
INST DIFFERENTIAL

EVENTS: Disabled
Figure 5-147: Instantaneous differential logic
XFMR HST FUNCTION:

Disabled
XFMR HST PICKUP:

140°C
XFMR HST DELAY:

1 min.
XFMR HST BLOCK:

Off
XFMR HST TARGET:

Self-Reset
GROUPED ELEMENTS
Range: Disabled, Enabled
Range: 2.000 to 30.000 pu in steps of 0.001
Range: FlexLogic operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
Range: Disabled, Enabled
Range: 50 to 300°C in steps of 1
Range: 0 to 30000 min. in steps of 1
Range: FlexLogic operand
Range: Self-reset, Latched, Disabled
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