Schweitzer Engineering Laboratories SEL-351 - Page 306

ii Breaker Monitor, Metering, and Load Profile Functions Date Code 20001006
SEL-351 Instruction Manual
Demand Meter Settings...................................................................................................8-24
Demand Current Logic Output Application – Raise Pickup for Unbalance Current...........8-26
Residual Ground Demand Current Below Pickup GDEMP.......................................8-27
Residual Ground Demand Current Goes Above Pickup GDEMP..............................8-27
Residual Ground Demand Current Goes Below Pickup GDEMP Again....................8-27
View or Reset Demand Metering Information ..................................................................8-28
Via Serial Port.........................................................................................................8-28
Via Front Panel .......................................................................................................8-28
Demand Metering Updating and Storage..........................................................................8-28
Energy Metering.....................................................................................................................8-28
View or Reset Energy Metering Information....................................................................8-28
Via Serial Port.........................................................................................................8-28
Via Front Panel .......................................................................................................8-29
Energy Metering Updating and Storage ...........................................................................8-29
Maximum/Minimum Metering................................................................................................8-29
View or Reset Maximum/Minimum Metering Information ...............................................8-29
Via Serial Port.........................................................................................................8-29
Via Front Panel .......................................................................................................8-29
Maximum/Minimum Metering Updating and Storage.......................................................8-29
Load Profile Report (Available in Firmware Versions 1, 2, 3, and 4) .......................................8-30
Determining the size of the Load Profile Buffer................................................................8-33
Clearing The Load Profile Buffer ....................................................................................8-33
TABLES
Table 8.1: Breaker Maintenance Information for a 25 kV Circuit Breaker ..........................................8-2
Table 8.2: Breaker Monitor Settings and Settings Ranges...................................................................8-4
Table 8.3: Demand Meter Settings and Settings Range.....................................................................8-24
FIGURES
Figure 8.1: Plotted Breaker Maintenance Points for a 25 kV Circuit Breaker .......................................8-3
Figure 8.2: SEL-351 Relay Breaker Maintenance Curve for a 25 kV Circuit Breaker ..........................8-5
Figure 8.3: Operation of SELOGIC Control Equation Breaker Monitor Initiation Setting ......................8-6
Figure 8.4: Breaker Monitor Accumulates 10% Wear .........................................................................8-8
Figure 8.5: Breaker Monitor Accumulates 25% Wear .........................................................................8-9
Figure 8.6: Breaker Monitor Accumulates 50% Wear .......................................................................8-10
Figure 8.7: Breaker Monitor Accumulates 100% Wear .....................................................................8-11
Figure 8.8: Input IN7 Connected to Trip Bus for Breaker Monitor Initiation......................................8-14
Figure 8.9: DC Under- and Overvoltage Elements.............................................................................8-15
Figure 8.10: Create DC Voltage Elements with SELOGIC Control Equations .......................................8-16
Figure 8.11: Response of Thermal and Rolling Demand Meters to a Step Input (setting
DMTC = 15 minutes)...............................................................................................8-21
Figure 8.12: Voltage V
S
Applied to Series RC Circuit.........................................................................8-22
Figure 8.13: Demand Current Logic Outputs ......................................................................................8-25
Figure 8.14: Raise Pickup of Residual Ground Time-Overcurrent Element for Unbalance Current.......8-26
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