Siemens siprotec 7SA6 User Manual page 468

Functions
Table 6-15 Operational measured values
Measured values
ϕ
magnitude of the phase angle difference
diff
between line and busbar (for sychronism
check)
I , I active and reactive component of earth
EEa EEr
fault current
1 ) acc. to address  (refer to Sub-section 6.1.3)
3 ) with consideration of the factor  ,,SK &7 (refer to Sub-section 6.1.1)
Min/Max Values
and Average
Values
Limit Value /
Set Point
Monitoring
6-286
The computation of the operational measured values is also executed during an
existent system fault in intervals of approx. 0.5 s.
Minimum, maximum and long-term average values are calculated by the 7SA6. Time
and date of the last update of the values can also be read out. At any time the
min/max values can be reset via binary inputs, via DIGSI
control panel. Additionally, the reset can be carried out cyclically, beginning with a
preset point of time.
The time period of the average value window and the number of updates can be set
for the long-term average values. The corresponding min/max values can be reset via
binary inputs, via DIGSI
For an overview of the minimum, maximum and average values as well as their
meaning please refer to Subsection 6.21.6, "Average Calculation" and "Min/Max
Values"
Use to detect about operating conditions. If a preset limit value / set point is exceeded,
an alarm is generated. This alarm can also be allocated to output relays and LEDs. In
contrast to the actual protection functions the monitoring function operates in the
background; therefore it may not pick up if measured values are changed
spontaneously in the event of a fault and if protection functions are picked up. Since
an alarm is only output in case the limit value / set point is exceeded more than once,
the monitoring process cannot pick up directly before a trip.
Set points can be set for the following measured and metered values:
• IL1dmd>: exceeding a preset maximum average value in phase L1.
• IL2dmd>: exceeding a preset maximum average value in phase L2.
• IL3dmd>: exceeding a preset maximum average value in phase L3.
• I1dmd>: exceeding a preset maximum average value of the positive sequence
system currents.
• |Pdmd|>: exceeding a preset maximum average value of the active power
magnitude.
• |Qdmd|>: exceeding a preset maximum average value of the reactive power
magnitude.
• Sdmd>: exceeding a preset maximum average value of the apparent power.
• |cosϕ|<: untershooting a preset magnitude of the power factor
primary
°
A
2 ) acc. to address  (refer to Sub-section 6.1.3)
®
4 or via the integrated control panel.
secondary % in relation to
— —
mA —
®
4 or via the integrated
C53000-G1176-C133-1
7SA6 Manual