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6.1.3
General Protection Data
Rating of the
Protected System
General Line Data
7SA6 Manual
C53000-G1176-C156-2
General protection data (P.System Data 2) includes settings associated with all
functions rather than a specific protective or monitoring function. In contrast to the
Power System Data 1 (P.System Data 1) as discussed in Sub-section 6.1.1, these
settings can be changed over with the setting groups. To modify these settings, select
the SETTINGS menu option Group A (setting group A), and then Power System
Data 2 (P.System Data 2).
The other setting groups are Group B, Group C, and Group D, as described in
Subsection 6.1.2.
The rated primary voltage (line voltage) and rated primary current (phase) of the pro-
tected system are entered in the address 1103 FullScaleVolt. and 1104
FullScaleCurr.. These parameters influence the display of the operational meas-
ured values in percent. If these ratings correspond to those of the voltage and current
transformers, the settings are the same as those in address 203 and 205 (Section
6.1.1).
The settings of the line data in this case refers to the common data which is independ-
ent on the actual distance protection grading.
The line angle (Address 1105 Line Angle) may be derived from the line parameters.
The following applies:
X
L
ϕ
------ -
tan
=
R
L
where R
being the resistance and X
L
rameters may either apply to the entire line length, or be per unit of line length as the
quotient is independent of length. Furthermore it makes no difference if the quotients
were calculated with primary or secondary values.
The line angle plays an important role e.g. for the form of the polygons in the Distance
Protection or in the earth impedance matching with magnitude and angle.
Calculation example:
110 kV overhead line 150 mm
= 0.19 Ω/km
R'
1
= 0.42 Ω/km
X'
1
The line angle is computed as follows
X
X'
L
1
tan ϕ
------ -
------- -
=
=
=
R
R'
L
1
In address 1105 the setting Line Angle = 66° is entered.
The per unit length reactance X' is entered as relative quantity x', in address 1110 in
Ω/km, when for example the unit of length is given in km (Address 236, refer to Section
6.1.1 under "Units of Length" or under address 1112 in Ω/mile, when the unit of
length is given in Miles. The corresponding line length is entered in address 1111
Line Length in kilometres or under address 1113 Line Length in miles. If the unit
of length in address 236 is changed after the per unit length impedances in address
ϕ
or
the reactance of the protected line. The line pa-
L
2
with the following data
0.42 Ω/km
---------------------------- -
2.21
=
0.19 Ω/km
X
æ
ö
L
arc
tan
------ -
=
è
ø
R
L
ϕ
65.7°
=
Functions
6-17
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