ABB RELION REX640 Technical Manual page 815

1MRS759142 C
REX640
Technical Manual
GUID-23A13D60-4573-46B3-A8BB-AB60DC3DF1F1 V1 EN
Figure 439: Operating time curves for the overexcitation IDMT curve 4 ("OvExt
IDMT Crv4") for different values of the Time multiplier setting when
the Constant delay is 800 milliseconds
The activation of the OPERATE output activates the BLK_RESTART output.
If the excitation level increases above the set value when BLK_RESTART is active,
the OPERATE output is activated immediately.
If the excitation level increases above the set value when BLK_RESTART is not active
but COOL_ACTIVE is active, the OPERATE output is not activated instantly. In this
case, the remaining part of the cooling timer affects the calculation of the operate timer
as shown in Figure 440. This compensates for the heating effect and makes the overall
operate time shorter.
Section 4
Protection functions
809