DSE 8610 MKII, Operator'S Manual, Page: 158 / 188

Protections
057-254 ISSUE: 2 Page 158 of 188
6.9 EARTH FAULT IDMT ALARM
When the module is suitably connected using the ‘Earth Fault CT’. The module measures Earth Fault
and can optionally be configured to generate an alarm condition (shutdown or electrical trip) when a
specified level is surpassed.
If the Earth Fault Alarm is enabled, the controller begins following the IDMT ‘curve’ when the earth
fault current passes the Trip setting.
If the Trip is surpassed for an excess amount of time, the IDMT Alarm triggers (Shutdown or Electrical
Trip as selected in Action).
The larger the earth fault, the faster the trip. The speed of the trip is dependent upon the fixed
formula:
=
0.14
.
− 1
Where:
is the tripping time in seconds (accurate to +/- 5% or +/- 50ms (whichever is the greater))
is the actual measured current
is the trip point setting in current
is the time multiplier setting
The settings shown in the example below are a screen capture of the DSE factory settings, taken from
the DSE Configuration Suite software.
t
(time multiplier setting)
I
T
(trip point setting in current)