222 D90
PLUS
LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
GROUPED PROTECTION ELEMENTS CHAPTER 7: PROTECTION
Figure 197: Load encroachment configuration settings
The following settings are available.
Function
Range: Enabled, Disabled
Default: Disabled
This setting enables and disables the load encroachment element.
Source
Range: LINE (SRC 1), BKR 1 (SRC 2), BKR 2 (SRC 3)
Default: LINE (SRC 1)
This setting selects the signal source for the load encroachment element.
Minimum Voltage
Range: 0.000 to 3.000 pu in steps of 0.001
Default: 0.250 pu
This setting specifies the minimum positive-sequence voltage required for operation of
the element. When the voltage is below this threshold, a blocking signal is not asserted
by the element. When selecting this setting, remember that the D90
Plus
measures the
phase-to-ground sequence voltages regardless of the VT connection.
The nominal VT secondary voltage as specified in the
Phase VT Secondary setting is the
per-unit base for this setting.
Reach
Range: 0.02 to 250.00 ohms in steps of 0.01
Default: 1.00 ohms
This setting specifies the resistive reach of the element as shown in the load
encroachment characteristic. Enter this setting in secondary ohms and calculate it as
the positive-sequence resistance seen by the relay under maximum load conditions and
unity power factor.
Angle
Range: 5 to 50° in steps of 1
Default: 30°
This setting specifies the size of the blocking region as shown on the load encroachment
characteristic diagram and applies to the positive-sequence impedance.
Pickup Delay
Range: 0.000 to 65.535 seconds in steps of 0.001
Default: 0.000 seconds
This setting specifies a delay for the declaration of the load encroachment element
between the pickup and operate output states. It is normally set to zero.
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