Manual 37351A
MFR 11 Packages - Protection Relay
© Woodward
Page 33/59
Type of Monitoring
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NOTE
The following screen will not be displayed, if the parameter "
Volt.-Measuring
" is configured to
"
Phase to phase
" power measurement (refer to Voltage Measurement on page 29).
Volt. Monitoring
----------------
Monitoring for
Phase-neutral/Phase to phase
The unit can either monitor the phase-neutral voltages (four-wire system) or the
phase-phase voltages (three-wire system). Usually, for low-voltage system
(400/690V-version) the phase-neutral voltages are monitored, while for the me-
dium and high-voltage systems (100 V-version), the phase-phase voltages are
monitored. The monitoring of the phase-phase voltages is recommended to avoid a
phase-earth fault in a compensated or isolated mains resulting in the voltage protec-
tion tripping. The only effect on the screen "Voltage measuring" is the one de-
scribed in the above note. The settings in the screen "
Volt.-Monitoring
" do
have the following effects on the configuration screens:
Phase-neutral
The voltage at the terminals 1/2/3/4 (or 1/3/5/6 for 690 V versions)
is measured as a four-wire installation. All subsequent screens con-
cerning voltage measuring refer to phase-neutral voltage (V
Ph-N
). This
is indicated in the configuration screens by the supplement [
Phase-
N
].
Phase to phase
If the voltage system connected to the terminals 1/2/3/4 (or 1/3/5/6
for 690 V versions) is a three-wire system, this setting must be se-
lected. All subsequent screens concerning voltage measuring refer to
phase-phase voltage (V
Ph-Ph
). In the configuration screens, this is in-
dicated by the supplement [
V(ph-ph)
].
