56
UMG 511
Transients
Transient voltages are rapid, impulsive transient
oscillation processes in electrical networks. Tran-
sient voltages are not predictable with respect to
time and last for a limited period.
Transient voltages are caused by the effects of
lighting, due to switching operations or the trig-
gering of fuses.
• The UMG511 recognizes transients that are
longer than 50µs.
• The UMG511 monitors the voltage measure-
ment inputs on transients.
• There are two independent criteria for recogni-
zing transients.
• If a transient has been recognized, the wave
shape is saved in a transient recording.
• If a transient has been recognized, the limit
value is automatically increased by 20V, both
in automatic and manual modes. This automa-
tic increase of the limit value fades within 10
minutes.
• If another transient is recognized within the
next 60 seconds, this transient is recorded
with 512 points.
• You can display recorded transients with the
GridVis incident browser.
Mode (absolute)
If a scanning value exceeds the set limit value, a
transient is recognized.
• Off
- Transient monitoring is switched off
• Automatic
- Factory pre-setting. The limit
value is automatically calculated and is 110%
of the current 200 ms effective value.
• Manual
- Transient monitoring uses the adjus-
table limit value under „Peak“.