Schweitzer Engineering Laboratories SEL-700G Series, Instruction Manual

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4.57
Date Code 20170814 Instruction Manual SEL-700G Relay
Protection and Logic Functions
Group Settings (SET Command)
Figure 4.31 Loss-of-Field Logic Diagram
Set E40 := Y to enable loss-of-field protection elements. If loss-of-field
protection is not necessary, set E40 := N.
The Zone 1 element typically is applied as a tripping function. Zone 1
diameter and offset setting guidelines are described below. Set the Zone 1
offset equal to half the generator transient reactance, X'
d
, in secondary ohms.
Zone 1 loss-of-field tripping is typically performed with short or zero time
delay. Use the 40Z1D setting to add any necessary delay.
The 40Z1 Relay Word bit asserts without time delay when the measured
positive-sequence impedance falls within the Zone 1 mho circle defined by the
offset and diameter settings.
The 40Z1T Relay Word bit asserts 40Z1D seconds after 40Z1 asserts.
The Zone 2 element typically is applied as a time-delayed tripping function.
Zone 2 diameter and offset setting guidelines are described below.
Impedance
Calculation
40Z1D
0
40Z2D
0
Relay
Word
Bits
Zone 1
Calculation
Zone 2
Calculation
SEL
OGIC
Setting
Setting
Z1
Ω
40Z1T
40DIR
40Z2T
40Z2
40Z1
40Z2P
40XD2
40Z1P
40XD1
Table 4.10 Loss-of-Field Protection Settings
Setting Prompt Setting Range
Setting Name :=
Factory Default
LOSS OF FIELD EN Y, N E40 := Y
Z1 MHO DIAMETER OFF, 0.1–100 ohm
a
a
Ranges and default settings shown are for 5 A CT. Multiply by 5 for 1 A rated CTs.
40Z1P := 13.4
a
Z1 OFFSET –50.0 to 0.0 ohm
a
40XD1 := –2.5
a
Z1 TIME DELAY 0.00–400.00 s 40Z1D := 0.00
Z2 MHO DIAMETER OFF, 0.1–100 ohm
a
40Z2P := 13.4
a
Z2 OFFSET –50.0 to 50.0 ohm
a
40XD2 := –2.5
a
Z2 TIME DELAY 0.00–400.00 s 40Z2D := 0.50
Z2 DIR ANGLE –20.0 to 0.0 deg 40DIR := –10
40Z TRQCTRL SEL
OGIC
40ZTC := NOT LOPX