CHAPTER 6: PROTECTION SETPOINTS POWER ELEMENTS
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL 6–133
CURRENT
Range: Calculated IN, Measured IG
Default: Calculated IN
The element responds to the neutral current (that is, three times zero-sequence current),
either calculated internally from the phase currents or supplied externally via the
ground CT input from more accurate sources such as the core balanced CT. The setting
allows selecting the source of the operating current.
OPERATING CURRENT PICKUP
Range: 0.002 to 30.000 x CT in steps of 0.001 x CT
Default: 0.060 x CT
The setting specifies the current supervision level for the measurement of zero-
sequence power.
POWER PICKUP
Range: 0.001 to 1.200 CTxVT in steps of 0.001 CTxVT
Default: 0.100 CTxVT
The setting specifies the operating point of the element. A value of 1 CTxVT is a product
of the 1 VT voltage as specified for the overvoltage condition of this element, and 1 CT
current as specified for the overcurrent condition of this element.
REFERENCE POWER PICKUP
Range: 0.001 to 1.200 CTxVT in steps of 0.001 CTxVT
Default: 0.500 CTxVT
The setting is used to calculate the inverse time characteristic delay (defined by Sref in
the equations below). A value of 1 CTxVT represents the product of a 1 VT voltage (as
specified in the overvoltage condition for this element) and a 1 CT current (as specified in
the overcurrent condition for this element.
ECA
Range: 0 to 359° in steps of 1°
Default: 0°
The setting adjusts the maximum torque angle of the element. The operating power is
calculated as:
Where:
* indicates complex conjugate. By varying the element characteristic angle (ECA), the
element can be made to respond to forward or reverse direction in inductive, resistive,
or capacitive networks as shown in the Wattmetric characteristic angle response
diagram.
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