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2.19.2 Setting Hints
General
Setting Values
7UM62 Manual
C53000-G1176-C149-3
4002 U<
FNo. 06506
>BLOCK U<
4004 U<<
FNo. 06508
>BLOCK U<<
FNo. 000361
>FAIL:Feeder VT
refer Fig. 2-120 in
Subsection 2.38.1.4
FFM
FNo. 06503
>BLOCK U/V
Figure 2-71
Logic Diagram of the Undervoltage Protection
The undervoltage protection is only effective and accessible if it has been set during
the configuration of the protection functions (Section 2.2) at address 0140,
UNDERVOLTAGE = Enabled. Set Disabled if the function is not required. Address
4001 UNDERVOLTAGE is used to switch the function ON or OFF, or to block only the
trip command (Block Relay).
It must be considered that the positive phase-sequence system of the voltages and
thus also the pickup thresholds are evaluated as phase-to-phase quantities
(terminal voltage ⋅ √3). The first undervoltage protection stage is typically set to about
75% of % the nominal machine voltage, i.e. address 4002 U< = 75 V. The user must
select a value for the 4003 T U< time setting that ensures that voltage dips affecting
the operating stability are disconnected. On the other hand, the time delay must be
long enough to avoid disconnection in case of permissible short-time voltage dips.
For the second stage, a lower pickup threshold 4004 U<< e.g. = 65 V should be
combined with a shorter trip time 4005 T U<< e.g. = 0.5 s to perform an approximate
adaptation to the stability behaviour of the consumers.
All setting times are additional time delays which do not include the operating times
(measuring time, drop-out time) of the protective function.
The drop-out ratio can be adapted in small steps to the operating conditions at address
4006A U< DOUT RATIO.
Undervoltage Protection (ANSI 27)
FNo. 06533
U< picked up
4003 T U<
&
FNo. 06537
U<< picked up
4005 T U<<
&
OR
FNo. 06531
Undervolt. BLK
Tripping
FNo. 06539
matrix
U< TRIP
TMin
TRIP CMD
FNo. 06540
U<< TRIP
149
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