Chapter 3
Behaviour of the Isolation Unit
Page 8 of 20
Product Description ENS31
Version: A.02
Issue: 20.09.2005
3
Behaviour of the Isolation Unit
3.1 General
information
The ENS31 monitors the mains power supply and prevents uncontrolled
island effects developing in the event of a power failure or the mains be-
ing switched off.
It reacts to fluctuations in:
•
voltage,
•
frequency,
•
impedance
of each individual phase.
Note
The default settings can be changed, if necessary. The ENS manufac-
turer must be informed of these requirements, however, prior to con-
figuration.
3.2
Fluctuations in the mains power supply
The threshold values for the mains power supply are set as follows:
Fluctuation
Threshold value
Test interval
Overvoltage
300 V
Every 20 ms
(fast shutdown)
Overvoltage
264 V
Every 200 ms
Undervoltage
130 V
Every 20 ms
(fast shutdown)
Undervoltage
184 V
Every 200 ms
Disconnection from the mains is also triggered when the 10-minute aver-
age value of the mains supply exceeds the setpoint value of 230 V by
more than 10% (testing the mains quality).
