2-34 Relay Element Settings
Date Code 20020206 SEL-300G Instruction Manual
sequence undervoltage element, 27V1. The undervoltage element generally is set 80% of
nominal voltage for single machine busses and 87% for multimachine buses.
To enable and set the undervoltage element, set
V
1.732
VNOM•0.8
27V1P
YE27
=
=
Use any SEL
OGIC Control Equation variable to define a tripping condition for Zone 2 with
undervoltage:
seconds 0.00SVDO
seconds 0.25SV1PU
40Z227V1SV1
=
=
∗=
The Relay Word bit, SV1T, should be added to the SV4 SEL
OGIC Control Equation, along with
the Zone 1 and Zone 2 conditions discussed above, to cause generator breaker and field breaker
tripping. See Section 4: SEL
OGIC
®
Control Equations for additional information on relay
tripping logic and detailed setting examples.
Element Operating Characteristics
40Z1P = 1.0 pu
-Xd'
2
X
R
DWG: M300G047
Zone 1
Zone 2
40Z2P = Xd
Figure 2.17: Loss-of-Field Element Operating Characteristic,
Negative Zone 2 Offset
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