8.21
Date Code 20080213
Instruction Manual
SEL-351A Relay
Breaker Monitor and Metering
Demand Metering
Figure 8.11
Response of Thermal and Rolling Demand Meters to a Step Input
(setting DMTC = 15 minutes)
Thermal Demand Meter Response (EDEM = THM)
The response of the thermal demand meter in
(middle) to the step
current input (top) is analogous to the series RC circuit in
.
Thermal Demand
Meter Response
(EDEM = THM)
Th
ermal Demand Curr
ent (per unit
)
0
0
5
10
15
0.5
0.9
1.0
Time
(Minutes)
Rolling Demand
Meter Response
(EDEM = ROL)
R
olling Demand Curr
ent (per unit
)
DMTC = 15 minutes
0
0
5
10
15
.33
.67
1.0
Time
(Minutes)
Step Current
Input
Inst
ant
aneous Curr
ent (per unit
)
0
0
5
10
15
0.5
1.0
Time
(Minutes)
Summary of Contents for SEL-351A
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