ABB RELION REX640 Technical Manual page 825

1MRS759142 C
REX640
Technical Manual
If a drop-off situation occurs, that is, voltage restores above Voltage start value, before
OPERATE is activated, the function does not reset until maximum recovery time
under consideration has elapsed, that is, START output remains active.
LVRT curve is defined using time-voltage settings coordinates. The settings available
are Recovery time 1...Recovery time 10 and Voltage level 1...Voltage level 10. The
number of coordinates required to define a LVRT curve is set by Active coordinates
setting.
When Recovery time 1 is set to non-zero value, it results into
horizontal characteristics from point of fault till Recovery time 1.
Two examples of LVRT curve are defined in
corresponding settings in
It is necessary to set the coordinate points correctly in order to avoid
maloperation. For example, setting for Recovery time 2 should be
greater than Recovery time 1. Recovery time 1...Recovery time 10 are
the respective time setting from the point of fault.
GUID-9E2BD086-4C7C-4E77-9DCE-D3DDACF412C6 V1 EN
Figure 445: Low voltage ride through example curve A
Figure 445
Table 777.
Section 4
Protection functions
and Figure 446 with
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