FAIL
BLOCK
IRES
ALARM
Differential
current
monitoring
I3P
I_A
I_B
I_C
Io
Timer
t
Figure 745: Functional module diagram
Differential current monitoring
Differential current monitoring supervises the difference between the summed
phase currents I_A, I_B and I_C and the reference current I_REF.
The current operating characteristics can be selected with the
Start value
setting.
When the highest phase current is less than 1.0 × In, the differential current limit is
defined with
Start value
. When the highest phase current is more than 1.0 × In, the
differential current limit is calculated with the equation.
MAX I A I B I C Start value( _ , _ , _ ) ×
(Equation 315)
The differential current is limited to 1.0 × In.
Figure 746: CCSPVC operating characteristics
When the differential current I_DIFF is in the operating region, the FAIL output is
activated.
Supervision functions
1MRS759142 F
1312 REX640
Technical Manual
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