Start Value - DEMA 400 Series User Manual

4.3.2.2.2

Start Value

The display shows how many times the nominal current value starts when the protection is
active. Selection is made in (0.05-35) In range
4.3.2.2.3 Delay Type
The type of delay curve for protection is assigned from this option. This curves can be
selected from tables : Menu> Protection Settings> Protection and Reset Curves> Protection
and Reset Curves.
4.3.2.2.4 Operate Delay
The operation delay is the value that determines the characteristic of the protection curve with
the delay type. If the delay type is selected as DMT, delaytype is indicated the term tI >> and
can have a value in the range of (0.02 - 200) s. Operation delay can take a value between
(0.025 – 3.2), If the delay type is selected as one of the IDMT curves.
The TMS value is calculated based on several arguments such as features of the protected
facility and protection selectivity requirements.
4.3.2.2.5 TMS
The TMS value determines the characteristic of the protection curve together with the delay
type. TMS setting; The delay type is activated when one of the curves except DMT is
selected. TMS is calculated based on several arguments such as features of the protected
facility, protection selectivity requirements.TMS value can be selected between (0,025-5)s
4.3.2.2.6 Reset Type
Reset type and time indicates that, the protection function which starts counting with a current
above the specified current threshold, shows the curve and value that determines the duration
of the failure if the current falls below the threshold without tripping.
The reset type can be selected as DMT (constant time) and IDMT (reverse constant time)
according to the selected protection curve type. The reset types used by various protection
curves and their parameters are examined in Main Menu> Protection Settings> Protection and
Reset Curves.
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