Winco DSE7300 Series - Manual (Page 93)

DSE Model 7000 Series Control & Instrumentation System Operators Manual
Part No. 057-074 7000 Series OPERATING MANUAL ISSUE 5 15/10/2009 ADM 93
8.8 EARTH FAULT SHUTDOWN / ELECTRICAL TRIP ALARM
NOTE: Earth fault alarm is fitted to DSE7300 Series modules V2.0.0 and higher only. DSE7300 Series
Version 1 has Earth Fault current display only. DSE7200 Series have no Earth Fault functionality.
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 DSE7300 Series controller begins following the IDMT ‘curve’. If the Trip is
surpassed for an excess amount of time the Alarm triggers (Shutdown or Electric trip as selected in Action).
The higher the Earth Fault, the faster the trip. The speed of the trip is dependent upon the fixed formula :
T = K x 0.14 / ( ( I / I
s
) 0.02 -1 )
Where:
T is the tripping time in seconds (accurate to +/- 5% or +/- 50ms (whichever is the greater)
K is the time multiplier setting
I is the actual earth current measured
I
s
is the trip setting value
The settings shown in the example above are a screen capture of the DSE factory settings, taken from the DSE
Configuration Suite software.
8.8.1 EARTH FAULT TRIPPING CURVES
NOTE: DSE Factory setting is time multiplier (K) = 0.4
I
S
(Trip setting
value)
K (time multiplier setting)