CHAPTER 5: SETTINGS
GROUPED ELEMENTS
B30 BUS DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
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5
5.7.5.2 Neutral time overcurrent (ANSI 51N, IEC PTOC)
SETTINGS
GROUPED ELEMENTS
SETTING GROUP 1(6)
NEUTRAL CURRENT
NEUTRAL TOC1(6)
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
— This setting enables and disables the neutral time overcurrent protection element.
NEUTRAL TOC1 SIGNAL SOURCE
— This setting selects the signal source for the neutral time overcurrent protection element.
NEUTRAL TOC1 INPUT
— This setting selects how neutral current input quantities are interpreted by the B30. Inputs can be
selected as fundamental phasor magnitudes or total waveform RMS magnitudes as required by the application.
NEUTRAL TOC1 PICKUP
— This setting specifies the neutral time overcurrent pickup level in per-unit values.
NEUTRAL TOC1 CURVE
— This setting selects the inverse time overcurrent curve style.
NEUTRAL TOC1 TD MULTIPLIER
— This setting specifies a multiple of the base curve shape specified by the
CURVE
setting.
Programming this value to zero results in an instantaneous response to all current levels above pickup.
NEUTRAL TOC1 RESET
— The “Instantaneous” reset method is intended for applications with other relays, such as most static
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.
NEUTRAL IOC 1
NEUTRAL IOC 6
NEUTRAL TOC1
NEUTRAL TOC1
FUNCTION: Disabled
Range: Disabled, Enabled
NEUTRAL TOC1 SIGNAL
SOURCE: SRC 1
Range: SRC 1, SRC 2, SRC 3, SRC 4, SRC 5, SRC 6
NEUTRAL TOC1
INPUT: Phasor
Range: Phasor, RMS
NEUTRAL TOC1
PICKUP: 1.000 pu
Range: 0.020 to 30.000 pu in steps of 0.001
NEUTRAL TOC1
CURVE: IEEE Mod Inv
Range: see Overcurrent Curve Types table
NEUTRAL TOC1
TD MULTIPLIER: 1.00
Range: 0.00 to 600.00 in steps of 0.01
NEUTRAL TOC1
RESET: Instantaneous
Range: Instantaneous, Timed
NEUTRAL TOC1 BLOCK:
Off
Range: FlexLogic operand
NEUTRAL TOC1
TARGET: Self-reset
Range: Self-reset, Latched, Disabled
NEUTRAL TOC1
EVENTS: Disabled
Range: Disabled, Enabled
Summary of Contents for b30
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Page 486: ...5 278 B30 BUS DIFFERENTIAL SYSTEM INSTRUCTION MANUAL TESTING CHAPTER 5 SETTINGS 5 ...
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