23
The pulse length of the digital input signal does not affect time
synchronization.
If time synchronization messages are received from a communication
protocol as well, they have to be synchronized within ±0.5 minutes at
minute-pulse or ±0.5 seconds at second-pulse synchronization.
Otherwise the time difference may appear as rounding errors. If it is
possible that the synchronization messages from the communication
protocol are delayed more than 0.5 seconds, minute-pulse
synchronization must be used.
When the minute-pulse synchronization is active and long time format
is sent via a communication protocol, the protocol's second and
millisecond part is ignored. The protocol's minute part is rounded to
the nearest minute. Short time format is ignored altogether.
When the second-pulse synchronization is active and long or short time
format is sent via a communication protocol, the protocol's millisecond
part is ignored. The protocol's second-part is rounded to the nearest
second.
5.1.2. Measurements
The table below presents the measured values which can be accessed through the
HMI.
Table 5.1.2.-1 Measured values
Indicator Description
L1 Current measured on phase L1
L2 Current measured on phase L2
L3 Current measured on phase L3
I
0
Measured earth-fault current
ΔI Calculated phase unbalance
θ Calculated thermal level
I
1 minute
The average current of the three phase-to-
phase currents during one minute
I
n minute
The average current of the three phase-to-
phase currents during the specified time range
Max I The maximum of one-minute average current of
the I n_min
5.1.3. Configuration
The Fig. 5.1.3.-1 illustrates how the internal and digital input signals can be
configured to obtain the required protection functionality.
Feeder Protection Relay
Technical Reference Manual
REF 610REF 610
1MRS755310
To Next Page
Loading...
