Siemens siprotec 7SA522 User Manual

2 Functions
48
7SA522 Manual
C53000-G1176-C155-3
The line angle is computed as follows
In address  the setting /LQH$QJOH = 66° is entered.
Address  'LVWDQFH$QJOH specifies the angle of inclination of the R sections
of the distance protection polygons. Usually you can also set the line angle here as in
address . A slightly smaller angle will usually not be disadvantageous.
The directional values (power, power factor, work and related min., max., mean and
setpoint values), calculated in the operational measured values, are usually defined
with positive direction towards the protected object. This requires that the connection
polarity for the entire device was configured accordingly in the Power System Data 1
(compare also “Polarity of Current Transformers”, address ). But it is also possible
to define by setting the “forward” direction for the protection functions and the positive
direction for the power etc. differently, e.g so that the active power flow from the line
to the busbar is indicated in the positive sense. Set under address  34VLJQ
the option UHYHUVHG. If the setting is QRWUHYHUVHG (default), the positive direction
for the power etc. corresponds to the “forward” direction for the protection functions.
The reactance value X' of the protected line is entered as reference value [ at
address  in Ω/km if the distance unit was set as kilometer (address , see Sub-
section 2.1.3.1 at “Distance Unit”), or at address  in Ω/mile if mile was selected
as distance unit. The corresponding line length is entered in address  /LQH
/HQJWK in kilometres or under address  /LQH/HQJWK in miles. After entry of
reactance per unit of line length in address  or  or the unit of line length in
address  or , the unit of line length is changed in address  and the line
data must be entered again for the revised distance unit.
The capacitance value C' of the protected line is required for compounding in overvolt-
age protection. Without compounding it is of no consequence. It is entered as value
F at address  in µF/km if the distance unit was set to kilometer (address ,
see Subsection 2.1.3.1 at “Distance Unit”), or at address  in µF/mile if mile was
set as distance unit. After entry of capacitance per unit line length in address  or
 or the line length in address  or , the unit of line length is changed in
address  and the line data must be entered again for the revised distance unit.
When entering the parameters with a personal computer and DIGSI
®
the values may
optionally also be entered as primary values. The following conversion to secondary
quantities is then not required.
For conversion of primary values to secondary values the following applies in general:
Likewise, the following goes for the reactance setting of a line:
where
N
CT
= Current transformer ratio
N
VT
= Transformation ratio of voltage transformer

Siemens siprotec 7SA522 Specifications

General

Brand	Siemens
Model	siprotec 7SA522
Category	Protection Device
Language	English