Fast
transfer –
simulta-
neous
Enable/disable
Fast
transfer –
sequen�al
break
before
make
(FBBM)
Enable/disable
1st phase
transfer
Residual
voltage
transfer
Time
delayed
transfer
Enable/disable
Decoupling
Transfer
ini�a�on
Enable/disable Enable/disable Enable/disable
Figure 940: Transfer sequence steps
Fast transfer – simultaneous
A fast transfer takes place when both the main and the stand-by feeders are within
specified limit values at the moment of initiation, e.g. frequency slip and phase
angle difference are limited between the networks and the stand-by voltage lies
above a minimum value.
Fast transfer can be enabled with the setting
Enable fast transfer
. If
Enable fast
transfer
setting is set to “1>2”, then fast transfer is allowed to the direction from
feeder 1 to feeder 2. If
Enable fast transfer
setting is set to “2>1”, then fast transfer
is allowed to the direction from feeder 2 to feeder 1. Setting value “Both” allows
fast transfer to both directions. Fast transfer can be disabled by setting
Enable fast
transfer
to “Off”.
If
Enable FBBM
setting is set to “false”, then function executes simultaneous fast
transfer. In case
Enable FBBM
is set to “true”, then function executes sequential
transfer.
In simultaneous fast transfer circuit breaker open and close commands are issued at
the same time (see
Figure 941
)
For uninterrupted transfer, the HSABTC function carries out a fast transfer, under
the condition that busbar and stand-by feeder are synchronous and other criteria as
described below are satisfied. For this the circuit breaker open and close signals are
issued simultaneously to the respective circuit breakers of main feeder and standby
feeder.
The fast transfer occurs in the direction of feeder 1 to feeder 2, if following
conditions are fulfilled simultaneously:
• The FAST_READY (from Evaluation module) is TRUE
• The READY (from Evaluation module) is TRUE
• DISA_FAST input is FALSE
• DISA_1_2 input is FALSE
• Setting
Enable fast transfer
is “1 > 2” or “Both”
• Transfer is activated as described in transfer initiation
The simultaneous fast transfer minimizes the dead time without current flow.
Figure 941
shows fast transfer with current free transfer time (dead time) of about
20ms. The dead time depends on the used circuit breakers and settings and this can
be optimized.
1MRS759142 F
Control functions
REX640
Technical Manual
1773
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