P.3.121
Date Code 20151029 Protection Manual SEL-411L Relay
Protection Functions
Frequency Estimation
Figure 3.71 SEL-411L Alpha Quantity Calculation
NOTE:
These settings are available
only if you have enabled Global
advanced settings, EGADVS := Y.
Although you have the flexibility to select any of the available voltage for the
frequency estimation, the correlation between the selected voltages and the
breaker poles is fixed as Table 3.56 shows.
The single-pole open Relay Word bits SPOA, SPOB, and SPOC control the
correlation. During an open-pole condition, the relay assigns a value of zero
voltage to the phase associated with the open pole. For example, if the
A-phase of a single pole breaker (BK1TYP = 1 or BK2TYP = 1) is open,
SPOA asserts to indicate the open-pole condition. When SPOA asserts, the
relay substitutes zero volts for the VF01 and VF11 values. If you selected
VF01/VF11 = VAY, then the VF01/VF11 voltages are set to zero when SPOA
asserts. Likewise, if you selected VF01/VF11 = VBY, then the VF01/VF11
voltages are still set to zero and not VF02 and VF12. Take care to assign the
appropriate phase voltages to match the correlation shown in Table 3.56 when
using single-pole breakers.
FREQP
VF01
VF02
VF03
1
VF11
VF12
VF13
0
EAFSRC
(SEL
OGIC
)
VFn1 – 0.5 (VFn2 + VFn3)
Valpha
Frequency
Estimation
FREQ
DFDTP
FREQOK
FREQFZ
n = 0 or 1
Table 3.55 Frequency Estimation
Label Prompt
Default
Value
EAFSRC Alt. Freq. Source (SELOGIC Equation) NA
VF01 Local Freq. Source 1 (ZERO, VAY, VBY, VCY, VAZ, VBZ, VCZ) VAY
VF02 Local Freq. Source 2 (ZERO, VAY, VBY, VCY, VAZ, VBZ, VCZ) VBY
VF03 Local Freq. Source 3 (ZERO, VAY, VBY, VCY, VAZ, VBZ, VCZ) VCY
VF11 Alt. Freq. Source 1 (ZERO, VAY, VBY, VCY, VAZ, VBZ, VCZ) ZERO
VF12 Alt. Freq. Source 2 (ZERO, VAY, VBY, VCY, VAZ, VBZ, VCZ) ZERO
VF13 Alt. Freq. Source 3 (ZERO, VAY, VBY, VCY, VAZ, VBZ, VCZ) ZERO
Table 3.56 Voltage and Breaker Pole Correlation
Relay Word Bit Phase A Phase B Phase C
SPOA = 0 VF01/VF11 – –
SPOA = 10––
SPOB = 0 – VF02/VF12 –
SPOB = 1–0–
SPOC = 0 – – VF03/VF13
SPOC = 1––0
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