GE T60 Instruction Manual page 488

GROUPED ELEMENTS
The phase time overcurrent element can provide a specified time-delay operating characteristic versus the applied current
or be used as a simple definite time element. The phase current input quantities can be programmed as fundamental
phasor magnitude or total waveform RMS magnitude as required by the application.
Two methods of resetting operation are available: "Timed" and "Instantaneous" (see the Inverse TOC Curve Characteristics
section earlier for details on curve setup, trip times, and reset operation). When the element is blocked, the time
accumulator resets according to the reset characteristic. For example, if the element reset characteristic is set to
"Instantaneous" and the element is blocked, the time accumulator clears immediately.
The
PHASE TOC1 PICKUP
accomplished via the multipliers (Mvr) corresponding to the phase-phase voltages of the voltage restraint characteristic
curve (see the figure); the pickup level is calculated as Mvr times the
feature is disabled, the pickup level always remains at the setting value.
5
— This setting enables and disables the phase time overcurrent protection element.
FUNCTION
— Selects the signal source for the phase time overcurrent protection element.
SIGNAL SOURCE
— Selects how phase current input quantities are interpreted by the T60. Inputs can be selected as fundamental
INPUT
phasor magnitudes or total waveform RMS magnitudes as required by the application.
— Specifies the phase time overcurrent pickup level in per-unit values.
PICKUP
— Selects the time inverse overcurrent curve style.
CURVE
— Specifies a multiple of the base curve shape specified by the
TD MULTIPLIER
zero results in an instantaneous response to all current levels above pickup.
— The "Instantaneous" reset method is intended for applications with other relays, such as most static relays, which
RESET
set the energy capacity directly to zero when the current falls below the reset threshold. The "Timed" reset method can be
used where the relay must coordinate with electromechanical relays.
VOLTAGE RESTRAINT
— Assertion of the operand assigned to this setting blocks phase A of the phase time overcurrent element.
BLOCK A
— Enables and disables the logging of phase time overcurrent events in the sequence of events recorder.
EVENTS
5-270
PHASE TOC1 BLOCK C:

Off
PHASE TOC1

TARGET: Self-reset
PHASE TOC1

EVENTS: Disabled
setting can be reduced dynamically by a voltage restraint feature (when enabled). This is
Figure 5-151: Phase time overcurrent voltage restraint characteristic
— Enables and disables the phase time overcurrent voltage restraint feature.
Range: FlexLogic operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
setting. If the voltage restraint
PHASE TOC1 PICKUP
setting. Programming this value to
CURVE
T60 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 5: SETTINGS