GE L30 Instruction Manual page 449

CHAPTER 5: SETTINGS
The L30 contains protection elements for ground time overcurrent (ANSI device 51G) and ground instantaneous
overcurrent (ANSI device 50G).
5.7.6.2 Ground time overcurrent (ANSI 51G, IEC PTOC)
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  GROUND CURRENT  GROUND TOC1(6)
 GROUND TOC1

This element can provide a required time-delay operating characteristic versus the applied current or be used as a simple
definite time element. The ground current input value is the quantity measured by the ground input CT and is the
fundamental phasor or RMS magnitude. Two methods of resetting operation are available: "Timed" and "Instantaneous"
(see the Inverse TOC Curve Characteristics section for details). 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.
— This setting enables and disables the ground time overcurrent protection element.
GROUND TOC1 FUNCTION
GROUND TOC1 SIGNAL SOURCE
— This setting selects how ground current input quantities are interpreted by the L30. Inputs can be
GROUND TOC1 INPUT
selected as fundamental phasor magnitudes or total waveform RMS magnitudes as required by the application.
— This setting specifies the ground time overcurrent pickup level in per-unit values.
GROUND TOC1 PICKUP
— This setting selects the inverse time overcurrent curve style.
GROUND TOC1 CURVE
— This setting specifies a multiple of the base curve shape specified by the
GROUND TOC1 TD MULTIPLIER
Programming this value to 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
GROUND TOC1 RESET
relays, which 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.
— Assertion of the operand assigned to this setting blocks operation of the ground time overcurrent
GROUND TOC1 BLOCK
element.
— This setting enables and disables the logging of ground time overcurrent events in the sequence
GROUND TOC1 EVENTS
of events recorder.
L30 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
GROUND TOC1

FUNCTION: Disabled
GROUND TOC1 SIGNAL

SOURCE: SRC 1
GROUND TOC1

INPUT: Phasor
GROUND TOC1

PICKUP: 1.000 pu
GROUND TOC1

CURVE: IEEE Mod Inv
GROUND TOC1

TD MULTIPLIER: 1.00
GROUND TOC1

RESET: Instantaneous
GROUND TOC1 BLOCK:

Off
GROUND TOC1

TARGET: Self-reset
GROUND TOC1

EVENTS: Disabled
— This setting selects the signal source for the ground time overcurrent protection element.
GROUPED ELEMENTS
Range: Disabled, Enabled
Range: SRC 1, SRC 2
Range: Phasor, RMS
Range: 0.020 to 30.000 pu in steps of 0.001
Range: see the Overcurrent Curve Types table
Range: 0.00 to 600.00 in steps of 0.01
Range: Instantaneous, Timed
Range: FlexLogic operand
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
5
setting.
CURVE
5-235