Sel SEL-787 - Demand Metering; Figure 4.46 Loss-Of-Potential (LOP) Logic; Table 4.25 Demand Meter Settings

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SEL-787 Relay Instruction Manual Date Code 20150130
Protection and Logic Functions
Demand Metering
Figure 4.46 Loss-of-Potential (LOP) Logic
Demand Metering
The SEL-787 provides demand and peak demand metering, selectable
between thermal and rolling demand types, for the following values for either
Winding 1 or Winding 2 currents:
➤ IA, IB, IC, phase currents (A primary)
➤ IG Residual ground current (A primary; IG = 3I0 = IA + IB + IC)
➤ 3I2 Negative-sequence current (A primary)
Table 4.25 shows the demand metering settings. Also refer to Section 5:
Metering and Monitoring and Section 7: Communications for other related
information for the demand meter.
60
S
R
Q
Q
0
0
60
1
0
LOP
| V1 | > 5 V
Δ| V1 | > 25%
Δ | I1 | > 0.1 • I
NOM
Δ | I2 | > 0.1 • I
NOM
Δ | I0 | > 0.1 • I
NOM
| V2 | < 5 V
| V0 | < 5 V
| V1 | > 0.75 • Nominal Voltage
(RESET has priority)
Note: I
NOM
is 1 A or 5 A depending on the part number.
I
NOM
is the phase secondary input rating.
Timer PU and DO times
are in cycles.
Relay
Word
Bit
Δ I1 > 10°
Δ I2 > 10°
Δ I0 > 10°
Table 4.25 Demand Meter Settings
Setting Prompt Setting Range
Setting Name :=
Fac tory Default
ENABLE DEM MTR OFF, W1, W2 EDEM := OFF
DEMAND MTR TYPE THM, ROL DEMTY := THM
DEM TIME CONSTNT 5, 10, 15, 30, 60 min DMTC := 5
PH CURR DEM LVL OFF, 0.50-16.00 A
a
OFF. 0.10-3.20 A
b
a
For In om = 5 A.
b
For In om = 1 A.
PHDEMP := 5.00
a
PHDEMP := 1.00 b
RES CURR DEM LVL OFF, 0.50-16.00 A
a
OFF, 0.10-3.2 A
b
GNDEMP := 1.00
a
GNDEMP := 0.20
b
3I2 CURR DEM LVL OFF, 0.50-16.00 A
a
OFF, 0.10-3.2 A
b
3I2DEMP := 1.00
a
3I2DEMP := 0.20
b