Alarms Associated with Measurements
Presentation
MicroLogic 5, 6, and 7 trip units monitor measurements using:
-
One or two pre-alarms (depending on the type of trip unit) assigned to:
-
Long-time protection (PAL Ir) for the MicroLogic 5 trip unit
-
Long-time protection (PAL Ir) and ground-fault protection (PAL Ig) for the MicroLogic 6 trip unit
-
Long-time protection (PAL Ir) and earth-leakage protection (PAL IΔn) for the MicroLogic 7 trip unit.
By default, these alarms are active.
-
-
Ten alarms defined by the user as required. The user assigns each of these alarms to a measurement.
By default, these alarms are not active.
All the alarms associated with measurements are accessible:
-
Using the communication network
-
On the FDM121 display
The alarms associated with measurements can be assigned to an SDx module output using EcoStruxure Power Commission software.
Alarm Setup
Select user-defined alarms and set their functions using EcoStruxure Power Commission software.
Alarm setup consists of:
-
Selecting the alarm priority level
-
Setting the alarm activation thresholds and time delays
The alarm description tables indicate for each of the alarms:
-
The setting range (thresholds and time delays)
-
The default setting values
Alarm Priority Level
Each alarm is assigned a priority level:
-
High priority
-
Medium priority
-
Low priority
-
No priority
Alarm indication on the FDM121 display depends on the alarm priority level.
The user sets the priority level of each alarm, according to the urgency of the action required.
By default, alarms are medium priority, except for alarms associated with operating indicators which are low priority.
Alarm Activation Conditions
An alarm associated with a measurement is activated when:
-
Values rise above the measurement pickup threshold for overvalue conditions.
-
Values drop below the measurement pickup threshold for undervalue conditions.
-
Values equal to the measurement pickup threshold for equality conditions.
The alarm activation condition can be preset by using EcoStruxure Power Commission software.
Overvalue Condition
Activation of the alarm on overvalue condition is determined using two thresholds and two time delays.
Undervalue Condition
Activation of the alarm on an undervalue condition is determined using two thresholds and two time delays.
Equality Condition
The alarm is activated when the associated monitored quantity equals the pickup threshold.
The alarm is deactivated when the associated monitored quantity is different from the pickup threshold.
Alarm activation is determined using the pickup/drop-out thresholds.
Management of Time Delays (Overvalue or Undervalue Conditions)
The alarm time delays are managed by two counters that are normally at 0.
For the pickup threshold, the time delay counter is:
-
incremented when the activation condition is fulfilled.
-
decremented if the activation condition is no longer fulfilled (before the end of the pickup time delay).
If the deactivation condition is reached, the pickup time delay counter is reset and the drop-out time delay counter is incremented.
For the drop-out threshold, the same principle is used.
Example: Management of the time delay on an overvoltage alarm (code 79)
1 Evolution of the voltage
2 Pickup time delay counter at 5 s
3 Drop-out time delay counter at 2 s
4 Overvoltage alarm: pickup zone (in green)
The alarm pickup time delay counter trips when the voltage crosses 500 V threshold. It is incremented or decremented according to the value of the voltage in relation to the threshold.
The alarm drop-out time delay counter trips when the voltage drops back below the 420 V threshold.