Sel 751A - Demand Metering; Reclose Supervision Setting (79 CLS); Table 4.30 Demand Meter Settings

4.76
SEL-751A Relay Instruction Manual Date Code 20100129
Protection and Logic Functions
Demand Metering
79SEQ := 79RS AND 51P1P AND (logical 0) = Logical 0
The shot counter stays at shot = 1.
Thus, if there is a coincident fault between the SEL-751A and the line
recloser, the SEL-751A will operate on 51AT, 51BT, or 51CT and then
reclose once, instead of going straight to the Lockout State (shot = 1 <
last shot = 2).
As stated earlier, the reset time setting 79RSD takes the shot counter
back to shot = 0 after a sequence coordination operation increments
the shot counter. Make sure that reset time setting 79RSD is set long
enough to maintain the shot counter at shot = 1 as shown in
Figure 4.39.
Reclose Supervision
Setting (79CLS)
See Reclose Supervision Logic on page 4.54.
Demand Metering
The SEL-751A provides demand and peak demand metering, selectable
between thermal and rolling demand types, for the following values:
➤ 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 4.30 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.
The demand current level settings are applied to demand current meter outputs
as shown in Figure 4.40.
Table 4.30 Demand Meter Settings
Setting Prompt Setting Range
Setting Name :=
Facto ry Defau lt
ENABLE DEM MTR THM, ROL EDEM := 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 I
NOM
=5 A.
b
For I
NOM
=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