Schweitzer Engineering Laboratories SEL-421-4 - Page 1032

7.8
SEL-400 Series Relays Instruction Manual Date Code 20171006
Metering
Demand Metering
Demand Metering Settings
Use the demand metering enable setting EDEM to select the demand metering
type (thermal or rolling) appropriate to your needs. Use demand pickup settings
(typically PDEMP, QDEMP, and GDEMP) to set alarm thresholds to notify you
when demand currents exceed preset operational points.
Figure 7.4 Rolling Demand Metering
Step
Current
Input
Rolling
Demand
Meter
Response
(EDEM := ROL)
1.0
1.0
.67
.33
0
0.5
0
DMTC Period
(a)
0
5
10
15
Time
(minutes)
0
5
10
15
Time
(minutes)
Step
Current
Input
Rolling
Demand
Meter
Response
(EDEM := ROL)
1.0
1.0
.67
.33
0
0.5
0
DMTC Period
(b)
0
5
10
15
Time
(minutes)
0
5
10
15
Time
(minutes)
Step
Current
Input
Rolling
Demand
Meter
Response
(EDEM := ROL)
1.0
1.0
.67
.33
0
0.5
0
DMTC Period
(c)
0
5
10
15
Time
(minutes)
0
5
10
15
Time
(minutes)
Step
Current
Input
Rolling
Demand
Meter
Response
(EDEM := ROL)
1.0
1.0
.67
.33
0
0.5
0
DMTC Period
0
5
10
15
Time
(minutes)
0
5
10
15
Time
(minutes)
(d)