ABB 615 series Technical Manual page 825

1MAC059074-MB A
615 series ANSI
Technical Manual
Figure 418 shows an example configuration, which enables the measurement of setting Ph
capacitive React.
ACTIVE (79)
TRIP (51P)
OR
TRIP (67/51N)
PICKUP (59N,59G)
PICKUP (67/51N) NOT
CB_CLOSE
DC_CLOSE
GUID-81245FF2-702E-4B96-9845-CFA749D428B5 V1 EN
Figure 418: An example configuration, which enables the measurement of setting Ph
capacitive React
If the ground fault is detected by the residual overvoltage function (PICKUP of 59N,
59G), but not seen by the forward-looking ground-fault protection function (PICKUP of
67/51N), the fault is located outside the protected feeder. This is mandatory for valid
measurement of setting Ph capacitive React. After a set delay (TON), the input
TRIGG_XC0F is activated and the parameter XC0F Calc in the recorded data is updated.
The delay (TON) must be set longer than the pickup delay of the directional ground-fault
function 67/51N, but shorter than the minimum trip time of the directional ground-fault
functions in any of the feeders. For example, if the pickup delay is 100 ms and the shortest
trip time 300 ms, a value of 300 ms can be used. Circuit breaker and disconnector status
is used to verify that the entire feeder is measured.
Modeling a non-homogeneous line
A typical distribution feeder is built with several different types of overhead lines and
cables. This means that the feeder is electrically non-homogeneous. 21FL allows the
modeling of the line impedance variation in protection relay with three line sections with
independent impedance settings. This improves the accuracy of physical fault distance
conversion done in the protection relay, especially in cases where the line impedance non-
homogeneity is severe. Each section is enabled by entering a section length, which differs
from zero, to settings Line Len section A, Line Len section B or Line Len section C in the
order section A-> section B-> section C.
Impedance model with one line section is enabled by setting Line Len section A to differ
from zero. In this case the impedance settings R1 line section A, X1 line section A, R0 line
section A and X0 line section A are used for the fault distance calculation and for
conversion from reactance to physical fault distance. This option should be used only in
the case of a homogeneous line, that is, when the protected feeder consists of only one
conductor type.
Impedance model with two line sections is enabled by setting both Line Len section A and
Line Len section B to differ from zero. In this case the impedance settings R1 line section
A, X1 line section A, R0 line section A, X0 line section A, R1 line section B, X1 line section
B, R0 line section B and X0 line section B are used for the fault distance calculation and for
conversion from reactance to physical fault distance. This option should be used in the
21FL
BLOCK
TRIGG
TRIGG_XC0F
TON
AND
Protection related functions
ALARM
Section 5
819