Date Code 20010731 Metering and Monitoring 6-1
SEL-352-1, -2 Instruction Manual
SECTION 6: METERING AND MONITORING
INTRODUCTION
The SEL-352 Relay provides metering information in several formats for the three-phase
winding current input. In addition, a Breaker Monitor function records breaker trips, the
cumulative current interrupted over time, and the amount of estimated contact wear. A Breaker
Resistor Thermal Monitor tracks the temperature of the close and open resistor for each of the
three phases. The relay also conducts a number of self-tests and provides warning and failure
alarms.
METERING
The MET command generates metering reports similar to the following example. The report
shows the TRMID setting, the date and time the report was displayed, and column labels as a
header. The values displayed include phase-to-neutral and phase-to-phase voltages and currents
in primary kilovolts and amperes, and real and reactive power in megawatts and megavars.
=>MET<ENTER>
EXAMPLE: BUS B, BREAKER 3 Date: 02/01/96 Time: 15:15:24.640
A B C AB BC CA
I (A) 202 198 197 349 339 344
VX(kV) 134.1 133.7 133.5 231.5 230.9 231.9
VY(kV) 134.0 133.8 133.6 231.5 230.9 231.9
dV(kV) 0.371 0.425 0.877
P (MW) 78.61
Q (MVAR) 13.85
=>
Metering Calculations
Currents are calculated based on the following (B and C are similar):
IA = Magnitude of (IA analog input) • (CTR)
IAB = Magnitude of [(IA analog input) – (IB analog input)] • (CTR)
Voltages are calculated based on the following (B and C are similar):
VXA = Magnitude of (VXA analog input) • (XPTR) / 1000
VXAB = Magnitude of [(VXA analog input) – (VXB analog input)] • (XPTR) / 1000
VYA = Magnitude of (VYA analog input) • (YPTR) / 1000
VYAB = Magnitude of [(VYA analog input) – (VYB analog input)] • (YPTR) / 1000
dVA = Magnitude of [(VXA analog input) • (XPTR) – (VYA analog input) • (YPTR)] /
1000
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