ABB REO 517 Applications Manual page 362

352
Monitoring of AC analog measurements
The dead-band limits can be set directly in the corresponding units of the observed
quantity for the:
• Amplitude dead-band supervision (ADBS)
• Integrating dead-band supervision (IDBS)
The IDBS area is defined by the following formula:
IDeadB
IDBS IDe adB ts
= ------------- --------------- - =
ReadFreq
Where:
IDeadB is a set operating value for IDBS in corresponding unit.
ReadFreq is the reading frequency. It has a constant value of 1Hz.
ts = 1/ReadFreq is the time between two samples (fixed to 1s).
The setting value for IDBS is IDeadB, and is expressed in the measuring unit of the
monitored quantity (kV, A, MW, Mvar, MVA or Hz). The value is reported if the time
integral area is greater than the value IDBS.
If a 0.1 Hz variation in the frequency for 10 minutes (600 s) is the event that should
cause the reporting of the frequency monitored value, than the set value for IDeadB is
60 Hz.
The hysteresis can be set under the setting Hysteres.
Alarm and warning thresholds have to be set respectively under the settings HiAlarm
(LowAlarm) and HiWarn (LowWarn).
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