Custom Protection Curves - DEMA 400 Series User Manual

ANSI / IEEE Inverse Time Delay Curves (TMS=1)
4.3.1.4

Custom Protection Curves

400 Series Special Curves include inverse protection curves for electromechanical relays,
constant time characteristic and reset curves. These curves are listed below.
1. SA Semic: Semiconductor Protection Curve.
2. SB DI: Definite Inverse Curve.
3. SC CO2: Short time Inverse Curve.
4. SD CO8: Long Time Inverse Curve.
5. SE CO-C3H: Standard Inverse Curve.
A
t= [ +B] ×TMS
I
a
-1
( )
I
s
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