Siemens siprotec 7SA522 User Manual

2.1 General
49
7SA522 Manual
C53000-G1176-C155-3
The following applies for the capacitance per distance unit:
Calculation Example:
110 kV overhead line 150 mm
2
as above
R'
1
= 0.19 Ω/km
X'
1
= 0.42 Ω/km
C' = 0.008 µF/km
Current Transformer 600 A/1 A
Voltage transformer 110 kV / 0.1 kV
The secondary per distance unit reactance is therefore:
In address  the setting [ = 0.229 Ω/km is entered.
The secondary per distance unit capacitance is therefore:
In address  the setting F = 0.015 µF/km is entered.
Earth Impedance
(Residual) Com-
pensation
Setting of the earth to line impedance ratio is an essential prerequisite for the accurate
measurement of the fault distance (distance protection, fault locator) during earth
faults. This compensation is either achieved by entering the resistance ratio R
E
/R
L
and
the reactance ratio X
E
/X
L
or by entry of the complex earth (residual) compensation
factor K
0
. Which of these two entry options applies was determined by the setting in
address  )RUPDW== (refer to Section 2.1.3.1). Corresponding to the option
determined there, only the relevant addresses appear here.
Earth Impedance
(Residual) Com-
pensation with
Scalar Factors
R
E
/R
L
and X
E
/X
L
.
When entering the resistance ratio R
E
/R
L
and the reactance ratio X
E
/X
L
the addresses
 to  apply. They are calculated separately, and do not correspond to the real
and imaginary components of Z
E
/Z
L
. A computation with complex numbers is therefore
not necessary! The ratios are obtained from system data using the following formulas:
Resistance ratio: Reactance ratio:

Siemens siprotec 7SA522 Specifications

General

Brand	Siemens
Model	siprotec 7SA522
Category	Protection Device
Language	English