11WL Circuit Breaker Selection and Application Guide
WL Circuit Breaker
Electronic Trip Unit (ETU)
Power metering function
In addition to excellent protection capabilities, the WL ETU has
unparalleled power metering functionality. True RMS current
sensing for metering is obtained from the same current sensors
used for overload protection. ETU power metering can measure
the following:
Potential transformers (PTs) are required to step down the
supply voltage to a level that is suitable for local input
connection to the breaker. PTs must be wired to the secondary
connections of the breaker and configured for three-phase,
three-wire or three-phase, four-wire supply system. The
measured values can be sent to a central database for
future power analysis or consumption reports.
Metering is not field installable – it must be configured in
the initial breaker purchase.
Event log
The event log is very extensive. Information regarding the
list of events can be found in the WL operation manual or
communication guide. Some of the event log categories are:
• Warnings
• Trip Logs
• Set-points
• Maintenance Detail
• CubicleBus Conditions
• Waveform Displays
Measured value Value range Accuracy
Currents Ia, Ib, Ic, In 30 ... 8000A ± 1%
Ground-fault current Ig (measure with external Gnd transformer) 100 ... 1200A ± 5%
Line-to-line voltages Vab, Vbc, Vca 80 ... 120% Vn ± 1%
Line-to-neutral voltages Van, Vbn, Vcn 80 ... 120% Vn ± 1%
Average value of phase-to-phase voltages V L-L AVG 80 ... 120% Vn ± 1%
Apparent power kVA per phase 13 ... 8000kVA ± 2%
Total apparent power KVA 13 ... 24000kVA ± 2%
Active power kW per phase -8000 ... 8000kW ± 3% (power factor > 0.6)
Total active power kW total -24000 ... 24000kVA ± 3% (power factor > 0.6)
Reactive power kvar -6400 ... 6400kvar ± 4% (power factor > 0.6)
Total reactive power kvar -20000 ... 20000kvar ± 4% (power factor > 0.6)
Power factor per phase -0.6 ... 1 ... 0.6 ± 0.04
Power factor total -0.6 ... 1 ... 0.6 ± 0.04
Demand of currents Ia, Ib, Ic 30 ... 8000A ± 1%
Average demand of 3-phase current 30 ... 8000A ± 1%
Demand kWD per phase 13 ... 8000kW ± 3% (power factor > 0.6)
kW demand 3-phase active power kWD total 13 ... 8000kW ± 3% (power factor > 0.6)
kVA demand kVA total 13 ... 8000kVA ± 2%
kVAR demand kVAR per phase 13 ... 8000kVA ± 2%
kVAR demand total -24000 ... 24000kvar ± 4% (power factor > 0.6)
kWhr imported 1 ... 10000MWh ± 2%
kWhr exported 1 ... 10000MWh ± 2%
kVARh imported 1 ... 10000Mvarh ± 4%
kVARh exported 1 ... 10000Mvarh ± 4%
Frequency 15 ... 440 Hz ± 0.1 Hz
Total harmonic distortions for current and voltage 2 ... 100% ± 3% from the meas. range up to the 29th harmonic
Phase unbalance for current and voltage 2 ... 150% ± 1%
Courtesy of NationalSwitchgear.com
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