12
Remote
transfer data
In addition to the event codes, the SPA bus
allows the substation level control data
communicator to read all the input data
( I-data), the setting values (S values), the
values recorded in the memory (V-data), and
some other data of the individual phase
modules of the differential relay. Further, part
of the information can be altered by commands
given over the SPA bus. All data are available
on channel 0, which needs not to be written in
data communication instructions .
Data
Code
Data
Values
direction
Input data
Load current measured on the HV
I1
R
0…50 x I
n
side and corrected by the CT
transforming ratio I
1
/I
n
Measured differential current
I2
R
0…50 x I
n
Load current measured on the LV
I3
R
0…50 x I
n
side and corrected by the CT
transforming ratio I
2
/I
n
Measured 2nd harmonic component
I4
R
0…33 x I
n
Harmonics blocking signal from
I5
R
0 = no blocking
the other phase modules
1 = blocking input active
Output data
Harmonics blocking
O1
R
0 = no blocking
1 = blocking control alert
Tripping
O2
R
0 = no tripping
1 = tripping control active
Settings
Current basic starting value
S1
R
20…50 % I
n
setting p
Current setting of starting
S2
R
10...50 %
ratio s
Actual blocking threshold I
hr
>
S3
R
10...20 % I
d
setting
Actual setting of stage I>>
S4
R
20…30 x I
n
(This setting is automatically
(10…15 x I
n
)
halved should the bias current
fall below 33 % of the differen-
tial current)
Actual checksum of switchgroup
S5
R
0...255
SG1 (Vector group matching,
SG1/1...6, output relay latching,
SG1/7, and blocking mode, SG1/8,
selection)
B
