ABB RELION REX640, Техническое руководство, Страница: 1853 / 1960

one day, the three-second average values are used. If the observation period is one
day or longer, the ten-minute average values are used.
The maximum three-second or ten-minute mean voltage unbalance is recorded
during the active observation period. The observation period start time
PR_STR_TIME, observation period end time PR_END_TIME, maximum voltage
unbalance value during observation period active,
MAX_UNB_VAL and time of
occurrence
MAX_UNB_TIME are available through the Monitored data view. These
outputs are updated once
OBS_PR_ACT
deactivates.
10.4.5.6 Percentile calculator
The purpose of the Percentile calculator module is to find the voltage unbalance
level so that during the observation time 95 percent (default value of the
Percentile
unbalance setting) of all the measured voltage unbalance amplitudes are less than
or equal to the calculated percentile.
The computed output value
PCT_UNB_VAL
, below which the percentile of the values
lies, is available in the Monitored data view. The
PCT_UNB_VAL
output value is
updated at the end of the observation period.
If the output
PCT_UNB_VAL
is higher than the defined setting
Unbalance start val
at the end of the observation period, an alarm output
PCT_UNB_AL
is activated.
The
PCT_UNB_AL
output remains active for the whole period before the next period
completes.
The
BLOCK
input blocks the output
PCT_UNB_VAL
.
10.4.5.7 Recorded data
The information required for a later fault analysis is stored when the Recorded data
module is triggered. This happens when a voltage unbalance is detected by the
Voltage unbalance detector module.
Three sets of recorded data are available in total. The sets are saved in data banks
1...3. The data bank 1 holds the most recent recorded data. Older data are moved
to the subsequent banks (1 to 2 and 2 to 3) when a voltage unbalance is detected.
When all three banks have data and a new variation is detected, the latest data set is
placed into bank 1 and the data in bank 3 is overwritten by the data from bank 2.
The recorded data can be reset with the
RESET
binary input signal by navigating to
the HMI reset ( Main menu > Clear > Reset recorded data > VSQVUBx) or through
tools via communications.
When a voltage unbalance is detected in the system, VSQVUB responds with the
MN_UNB_AL
alarm signal. During the alarm situation, VSQVUB stores the maximum
magnitude and the time of occurrence and the duration of alarm
MN_UNB_AL
. The
recorded data is stored when
MN_UNB_AL
is deactivated.
Table 1644: Recorded data
Parameter Description
Alarm high mean Dur Time duration for alarm high mean unbalance
Max unbalance Volt Maximum three-second voltage
Time Max Unb Volt Time stamp of voltage unbalance
1MRS759142 F Power quality measurement functions
REX640
Technical Manual
1853