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F35 MULTIPLE FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
GROUPED ELEMENTS
CHAPTER 5: SETTINGS
5
Each of the six setting group menus is identical. Setting group 1 (the default active group) is active automatically when no
other group is active.
If the device incorrectly switches to group 1 after power cycling, upgrade the firmware to version 7.31 or later to correct
this issue.
5.7.3 Phase current
5.7.3.1 Menu
SETTINGS
GROUPED ELEMENTS
SETTING GROUP 1(6)
PHASE CURRENT
5.7.3.2 Inverse TOC curve characteristics
The inverse time overcurrent curves used by the time overcurrent elements are the IEEE, IEC, GE Type IAC, and I
2
t standard
curve shapes. This allows for simplified coordination with downstream devices.
If none of these curve shapes is adequate, FlexCurves can be used to customize the inverse time curve characteristics. The
definite time curve is also an option that can be appropriate if only simple protection is required.
Table 5-26: Overcurrent curve types
A time dial multiplier setting allows selection of a multiple of the base curve shape (where the time dial multiplier = 1) with
the curve shape (
CURVE
) setting. Unlike the electromechanical time dial equivalent, operate times are directly proportional
to the time multiplier (
TD MULTIPLIER
) setting value. For example, all times for a multiplier of 10 are 10 times the multiplier 1
or base curve values. Setting the multiplier to zero results in an instantaneous response to all current levels above pickup.
Time overcurrent time calculations are made with an internal
energy capacity
memory variable. When this variable
indicates that the energy capacity has reached 100%, a time overcurrent element operates. If less than 100% energy
capacity is accumulated in this variable and the current falls below the dropout threshold of 97 to 98% of the pickup value,
the variable must be reduced. Two methods of this resetting operation are available: “Instantaneous” and “Timed.” The
“Instantaneous” selection 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” selection can be used where the
relay must coordinate with electromechanical relays.
NEGATIVE SEQUENCE
CURRENT
VOLTAGE ELEMENTS
PHASE CURRENT
PHASE TOC 1
PHASE TOC 6
PHASE IOC 1
PHASE IOC 12
IEEE
IEC
GE type IAC
Other
IEEE Extremely Inverse
IEC Curve A (BS142)
IAC Extremely Inverse
I
2
t
IEEE Very Inverse
IEC Curve B (BS142)
IAC Very Inverse
FlexCurves A, B, C, and D
IEEE Moderately Inverse
IEC Curve C (BS142)
IAC Inverse
Recloser Curves
IEC Short Inverse
IAC Short Inverse
Definite Time
