9-46
Setting the Relay
Date Code 20010625
SEL-311L Instruction Manual
element used to torque control 51P. Note, Zone 2 phase distance must reach to Station T in the
presence of infeed. This reach requires a setting that may overreach the adjacent Zone 1 and
cause miscoordination if Zone 2 is allowed to trip after a definite time. Zone 3 overreaching time
delayed elements detect faults beyond Station R and function as a traditional Zone 2 time delayed
element.
Instantaneous/Definite-Time Overcurrent Enable Settings
Phase element levels (N, 1–3) (see Figure 3.42)
E50P = N
Residual ground element levels (N, 1–4) (see Figure 3.45)
E50G = N
Negative-sequence element levels (N, 1–4) (see Figure 3.46)
E50Q = N
Instantaneous overcurrent elements are not required in this application.
Time-Overcurrent Enable Settings
Phase element (Y, N) (see Figure 3.47)
E51P = Y
Residual ground element (Y, N) (see Figure 3.48)
E51G= Y
Negative-sequence element (Y, N) (see Figure 3.49)
E51Q= N
Use 51PT and 51GT to provide backup protection for the protected 230 kV line.
Other Enable Settings
Directional control (Y, AUTO)
(see
Directional Control Settings
in
Section 4
)
E32 = AUTO
Enable
Best Choice Ground Directional
™ Logic with E32 = AUTO. This automatically calculates
and sets Z2F, Z2R, 50QFP, 50QRP, a2, k2, 50GRP, a0, Z0F, and Z0R. These settings must be
made manually if E32 = Y.
Out-of-Step (Y, N) (see Figure 3.41)
EOOS = N
Out-of-step is not used in this example. Set EOOS = N to disable out of step elements.
Load encroachment (Y, N) (see Figure 4.3)
ELOAD = N
Load encroachment is not required in this example.
At maximum load, Zload = (67 / 4.58) = 14.6 Ohms which is much larger than distance element
settings.
Set ELOAD = N to disable load-encroachment elements.
Switch-onto-fault (Y, N) (see Figure 5.5)
ESOTF = N
The SOTF logic permits tripping by specified protection elements for a definable time after circuit
breaker(s) close. Specify these elements in the TRSOTF SEL
OGIC
control equation.
Apply SOTF when using line-side relaying potentials. Since this example uses bus side relaying
potentials, set ESOTF = N.
Voltage elements (Y, N) (see Figures 3.50, 3.51, 3.52, and 3.53)
EVOLT = N
Voltage elements are not enabled in this example. Set EVOLT = N.
Synchronism check (Y, N) (see Figures 3.53 and 3.54)
E25 = N
Synchronism check elements are not enabled in this example. Set E25 = N.
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