CHAPTER 5: SETTINGS
GROUPED ELEMENTS
L30 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
5-229
5
The positive-sequence restraint must be considered when testing for pickup accuracy and response time (multiple of
pickup). The operating quantity depends on how test currents are injected into the relay (single-phase injection):
Eq. 5-23
NEUTRAL IOC1 FUNCTION
— This setting enables and disables the neutral instantaneous overcurrent protection element.
NEUTRAL IOC1 SIGNAL SOURCE
— This setting selects the signal source for the neutral instantaneous overcurrent protection
element.
NEUTRAL IOC1 PICKUP
— This setting specifies the neutral instantaneous overcurrent pickup level in per-unit values.
NEUTRAL IOC1 PICKUP DELAY
— This setting delays the assertion of the
NEUTRAL IOC OP
operands. It is used to achieve timing
coordination with other elements and relays.
NEUTRAL IOC1 RESET DELAY
— This setting specifies a delay for the reset of the neutral instantaneous overcurrent element
between the operate output state and the return to logic 0 after the input passes outside the defined pickup range. This
setting is used to ensure that the relay output contacts are closed long enough to ensure reception by downstream
equipment.a
NEUTRAL IOC1 BLOCK
— Assertion of the operand assigned to this setting blocks operation of the neutral instantaneous
overcurrent element.
NEUTRAL IOC1 EVENTS
— This setting enables and disables the logging of neutral instantaneous overcurrent events in the
sequence of events recorder.
Figure 5-115: Neutral IOC1 logic
5.7.5.4 Neutral directional overcurrent (ANSI 67N, IEC PDEF/PTOC)
SETTINGS
GROUPED ELEMENTS
SETTING GROUP 1(6)
NEUTRAL CURRENT
NEUTRAL DIRECTIONAL
OC1(2)
NEUTRAL
DIRECTIONAL OC1
NEUTRAL DIR OC1
FUNCTION: Disabled
Range: Disabled, Enabled
NEUTRAL DIR OC1
SOURCE: SRC 1
Range: SRC 1, SRC 2
NEUTRAL DIR OC1
POLARIZING: Voltage
Range: Voltage, Current, Dual, Dual-V, Dual-I
NEUTRAL DIR OC1 POL
VOLT: Calculated V0
Range: Calculated V0, Measured VX
NEUTRAL DIR OC1 OP
CURR: Calculated 3I0
Range: Calculated 3I0, Measured IG
NEUTRAL DIR OC1 POS-
SEQ RESTRAINT: 0.063
Range: 0.000 to 0.500 in steps of 0.001