GE C60 Instruction Manual page 431
Breaker protection system
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- Instruction manual (682 pages) ,
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- Instruction manual (604 pages)
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CHAPTER 5: SETTINGS
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.
— This setting enables and disables the neutral time overcurrent protection element.
NEUTRAL TOC1 FUNCTION
NEUTRAL TOC1 SIGNAL SOURCE
— This setting selects how neutral current input quantities are interpreted by the C60. Inputs can be
NEUTRAL TOC1 INPUT
selected as fundamental phasor magnitudes or total waveform RMS magnitudes as required by the application.
— This setting specifies the neutral time overcurrent pickup level in per-unit values.
NEUTRAL TOC1 PICKUP
— This setting selects the inverse time overcurrent curve style.
NEUTRAL TOC1 CURVE
NEUTRAL 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
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.
— Assertion of the operand assigned to this setting blocks operation of the neutral time overcurrent
NEUTRAL TOC1 BLOCK
element.
— This setting enables and disables the logging of neutral time overcurrent events in the sequence
NEUTRAL TOC1 EVENTS
of events recorder.
5.7.4.3 Neutral instantaneous overcurrent (ANSI 50N, IEC PIOC)
SETTINGS GROUPED ELEMENTS SETTING GROUP 1(6) NEUTRAL CURRENT NEUTRAL IOC1(8)
NEUTRAL IOC1
C60 BREAKER PROTECTION SYSTEM – INSTRUCTION MANUAL
NEUTRAL TOC1
TARGET: Self-reset
NEUTRAL TOC1
EVENTS: Disabled
— This setting selects the signal source for the neutral time overcurrent protection element.
— This setting specifies a multiple of the base curve shape specified by the
Figure 5-114: Neutral time overcurrent 1 logic
NEUTRAL IOC1
FUNCTION: Disabled
NEUTRAL IOC1 SIGNAL
SOURCE: SRC 1
GROUPED ELEMENTS
Range: Self-reset, Latched, Disabled
Range: Disabled, Enabled
Range: Disabled, Enabled
Range: SRC 1, SRC 2, SRC 3, SRC 4
setting.
CURVE
5
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