Timer 1
Once activated, the Timer 1 module activates the ST_OVLOD output. The operation
time depends on the overload level and
Time multiplier
. The operation time
under standard characteristics is based on ANSI/IEEE 37.99 and IEC 60871-1
recommendations.
Table 738: Standard Curve characteristics for IDMT Curve
Overload value IED operate time(s) with k =
1
Standard
1.10 43200 IEC60871-1
1.15 1800 IEC60871-1
1.20 300 IEC60871-1
1.30 60 ANSI/IEEE37.99,IEC60871-1
1.40 15 ANSI/IEEE37.99
1.70 1 ANSI/IEEE37.99
2.20 0.120 ANSI/IEEE37.99
Operate time is based on maximum value of I_PEAK_INT_A, I_PEAK_INT_B and
I_PEAK_INT_C. From maximum value calculated , operate time between any two
consecutive points in the standard table is based on logarithmic interpolation.
The operate time can be scaled using the
Time multiplier
setting. The OPR_OVLOD
output is activated if the overload situation lasts long enough to exceed the
operation time.
The operate time for the operation overload stage is limited between 0.1
s to 43200 s (12 hours) if
Time multiplier
is used.
1MRS757644 H Protection functions
620 series
Technical Manual
775
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