GE N60 Instruction Manual page 428

GROUPED ELEMENTS
5.7.5.2 Neutral time overcurrent (ANSI 51N, IEC PTOC)
SETTINGS  GROUPED ELEMENTS  SETTING GROUP 1(6)  NEUTRAL CURRENT  NEUTRAL TOC1(6)
 NEUTRAL TOC1

5
The neutral time overcurrent element can provide a desired time-delay operating characteristic versus the applied current
or be used as a simple definite time element. The neutral current input value is a quantity calculated as 3Io from the phase
currents and 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 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.
NEUTRAL TOC1 FUNCTION
NEUTRAL TOC1 SIGNAL SOURCE
NEUTRAL TOC1 INPUT
selected as fundamental phasor magnitudes or total waveform RMS magnitudes as required by the application.
NEUTRAL TOC1 PICKUP
NEUTRAL TOC1 CURVE
NEUTRAL TOC1 TD MULTIPLIER
Programming this value to zero results in an instantaneous response to all current levels above pickup.
NEUTRAL 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.
5-234
 NEUTRAL

 DIRECTIONAL OC1
 NEUTRAL

 DIRECTIONAL OC3
NEUTRAL TOC1

FUNCTION: Disabled
NEUTRAL TOC1 SIGNAL

SOURCE: SRC 1
NEUTRAL TOC1

INPUT: Phasor
NEUTRAL TOC1

PICKUP: 1.000 pu
NEUTRAL TOC1

CURVE: IEEE Mod Inv
NEUTRAL TOC1

TD MULTIPLIER: 1.00
NEUTRAL TOC1

RESET: Instantaneous
NEUTRAL TOC1 BLOCK:

Off
NEUTRAL TOC1

TARGET: Self-reset
NEUTRAL TOC1

EVENTS: Disabled
— This setting enables and disables the neutral time overcurrent protection element.
— This setting selects the signal source for the neutral time overcurrent protection element.
— This setting selects how neutral current input quantities are interpreted by the N60. Inputs can be
— This setting specifies the neutral time overcurrent pickup level in per-unit values.
— This setting selects the inverse time overcurrent curve style.
— This setting specifies a multiple of the base curve shape specified by the
— The "Instantaneous" reset method is intended for applications with other relays, such as most static
N60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUAL
See page 5-236

Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
Range: Phasor, RMS
Range: 0.020 to 30.000 pu in steps of 0.001
Range: see 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
CHAPTER 5: SETTINGS
setting.
CURVE