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Phase Rotation
Units of Length
Mode of Earth
Impedance
(Residual)
Compensation
Closing Time of the
Circuit Breaker
Trip/Close
Command Duration
Circuit Breaker
Test
6.1.1.1
Settings
Addr.
Setting Title
201
CT Starpoint
7SA6 Manual
C53000-G1176-C156-2
Address 235 PHASE SEQ. is used to establish the phase rotation. The preset phase
L1 L3 L2
sequence is "
dress 235 must be set accordingly.
Address 236 Distance Unit corresponds to the units of length (miles or km) ap-
plicable to fault locating. Changing the length unit will not result in an automatic con-
version. The new setting values must be entered at the appropriate addresses.
Matching of the earth to line impedance ratio is an essential prerequisite for the accu-
rate measurement of the fault distance (distance protection, fault location) during earth
faults. In address 237 Format Z0/Z1 the format for entering the residual compen-
sation is determined. It is possible to either use the ratio RE/RL and XE/XL or to enter
the complex earth (residual) impedance factor K0. The actual setting of the earth (re-
sidual) impedance factors is done in conjunction with the general protection data (refer
to Section 6.1.3).
The closing time of the circuit breaker T-CB close (address 239) is necessary if the
synchro-check function of the relay is used also for asynchronous switching. In this
case, the relay calculates the ideal closing instant such that the two voltages (bus bar
and feeder) are in synchronism at the instant when the breaker primary contacts close.
Under address 240A the minimum trip command duration TMin TRIP CMD is set.
This applies to all protection and control functions which may issue a trip command.
This also determines the length of the trip command pulse when a circuit breaker trip
test is initiated via the device. This setting can only be modified with DIGSI
"Additional Settings".
Under address 241A the maximum close command duration TMax CLOSE CMD is set.
This applies to all close commands issued by the device. It also determines the length
of the close command pulse when a circuit breaker test cycle is issued via the device.
It must be set long enough to ensure that the circuit breaker has securely closed.
There is no risk in setting this time too long, as the close command will in any event
be terminated following a new trip command from a protection function. This setting
can only be modified with DIGSI
With the 7SA6 it is possible to initiate from the front of the device or with DIGSI
on load circuit breaker test consisting of a trip and close command. The duration of the
commands is determined by the command duration settings above. With address 242
T-CBtest-dead the duration from the end of the trip command up to the start of the
close command for this test is determined. This setting should not be shorter than
0.1 s.
Note: The indicated secondary current values for setting ranges and default settings
refer to I
= 1 A. For the nominal current 5 A these values are to be multiplied by 5.
N
Addresses with an attached „A" can only be changed with DIGSI
Settings".
Setting Options
towards Line
towards Busbar
". For systems that use a phase sequence of "
®
4 under "Additional Settings".
Default Setting
towards Line
Functions
L1 L3 L2
®
®
4 in "Additional
Comments
CT Starpoint
", ad-
4 under
®
4 an
6-11
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