94
CET Electric Technology
and Mains-II Dip/Swell/Interruption Alarms will be evaluated against their respective Mains-
I/II PT Secondary (ULL) values. Also, the Nominal Voltage will be adjusted internally for Wye
and Delta modes accordingly, where ULL-I/II Nominal Voltage = Mains-I/II PT Secondary and
ULN-I/II Nominal Voltage = Mains-I/II PT Secondary ÷
√
3.
Therefore, it’s critical to set the
Nominal Voltage
correctly for the Dip/Swell/Interruption Alarms to work
properly
.
Dip/Swell/Interruption Alarm Limit = Nominal Voltage x Dip/Swell/Interruption Alarm Threshold
Dip/Interruption Alarm Return Limit = Dip/Interruption Alarm Limit x (1 + Universal Hysteresis)
Swell Alarm Return Limit = Swell Alarm Limit x (1 – Universal Hysteresis)
The logic diagram of Dip and Swell Alarms are illustrated in Figure 4-31 and Figure 4-32, respectively.
Figure 4-31 Dip Alarm Logic Diagram
Figure 4-32 Swell Alarm Logic Diagram
The logic diagram of Interruption Alarm is illustrated in Figure 4-33.
Figure 4-33 Interruption Alarm Logic Diagram
Dip/Swell and Interruption Alarms trigger both the SOE log and Waveform Recorder. The SOE and
Waveform Logs can be accessed via
Event Log => SOE/Waveform
on the Web Interface.
Figure 4-33 Dip/Swell Triggered SOE