Siemens SENTRON 3WL10 - Page 78

Measured values of the ETUs of the 3-series
Total number of trips No. —
Operating hours counter h —
Contact wear % Pre-alarm > 80%
Alarm = 100%
Date of maintenance performed  Last
Direction to perform necessary mainte‐
nance
 ––
Key data  Type of circuit breaker, name assigned to the device, serial number
Self-diagnostics
 Parameter Precision
Open-circuit detection
Watchdog: constant CT monitoring, moni‐
toring of the electronics and tripping coil
 Alarm due to discon‐
nection Current trans‐
former, rating plug,
tripping coil
Optional: Only alarm or tripping of the circuit
breaker
Temperature (T)  Pre-alarm and alarm
due to overheating
1)
If auxiliary power supply is connected
Metering functions of the ETUs of the 6-series
The electronic trip units of the 6-series can be expanded with the metering functions MF Basic
or MFAdvanced. These measure the voltage between the phases with internal voltage tap -
optionally on the incoming or outgoing feeder side, i.e. internally before or after the contact
interruption point - and can therefore calculate and transmit values for power, energy, phase
di󹪜erence, etc., taking the current signals into consideration.
• MF Basic provides many measured values in accordance with IEC61557‑12
• MF Advanced provides not only the measured values described but also many enhanced
protective functions, which are listed in Chapter Parameters of the trip units (Page 66). In this
way, the ETU can also power the metering module MFAdvanced directly from the busbar
itself if no auxiliary power supply is provided via the Breaker Connect module. Faults such as
overvoltages in the power system can therefore be detected before the contacts of the circuit
breaker are closed.
Metering functions of the ETUs of the 6-series

Instantaneous values
 Measured val‐
ues
Precision
Reference standard: IEC 61557-12
Metering mod‐
ule MF required
Currents (rms value) A L1, L2, L3, N 1%, Class1
Fixed lower current transmission limit
=3%I
n
—
Ground-fault current A I
g
2% —
Phase-to-phase voltage (rms value) V U12, U23, U31 0.5% ●
Phase-to-neutral voltage (rms value) V U1, U2, U3 0.5% ●
Phase sequence  — — ●
Description
2.9Electronic trip unit ETU
3VA27 molded case circuit breakers & 3WL10 air circuit breakers
Equipment Manual, 10/2023, L1V30499596002-03 77