Protection - DEMA 400 Series User Manual

4.3.5.5.1

Protection

It can be selected 'Active' or 'Passive'.According to the treshold situation, the protection is
activated in the active state and disabled in the passive state
4.3.5.5.2 Start Value
It is the screen where the treshold of Wattmetric Earth Protection is set when the protection is
active. This can be selected in the range of (10 – 800) Ien W
4.3.5.5.3 Delay Type
The type of delay curve to use for protection is assigned from this option. This curves ca be
selected from Menu> Protection Settings> Protection and Reset Curves> Protection and
Reset Curves Table.
4.3.5.5.4 Operate Delay
The operation delay determines the characteristic of the protection curve with the delay type.
Operation delay can take a value between (0.02-150)s if the delay type is selected as DMT. If
the delay type is selected as one of the IDMT curves, the delay is expressed by the term
"TMS" and the value in the process delay will be ineffective.
4.3.5.5.5 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
deactivation time if the current falls below the threshold without tripping.
The reset type can be selected as DMT (fixed 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.
4.3.5.5.6 Reset Delay
According to the menu settings, exceeding 5.00 In and without breaker tripping, It was
selected to count the DMT (constant time) reset time (0.04 s) after the current has dropped
below 5.00 In. Thus, after the current falls below the threshold, 40 ms will be counted. If the
Wattmetric Earth Fault Protection Display
102