ABB COM600 series User's & Technical Manual page 33

1MRS758734 COM600 series 5.1
Substation Analytics Technical Manual
changes, the value is no longer valid. In this case, the setting
should be updated, for example by repeating the test.
The calculation procedure of the Ph capacitive React setting is triggered by the binary
signal connected to the TRIGG_XC0F input when earth fault is conducted.
Figure 4.3-32 shows a configuration for the Ph capacitive React calculation triggering
that can be used for calculating XC0F_CALC.
• If the earth fault is detected by the residual overvoltage function (START of
ROVPTOV) and fault is not seen by forward-looking earth-fault protection function
(START of DEFLPDEF) that is set to direction "Reverse", then after a set delay
(TONGAPC), the XC0F_CALC output is updated. Correspondingly, if the fault
direction is found to be forward, the XC0F_CALC value does not describe the pro-
tected feeder and is not useful because triggering can be done only when the fault
is outside the protected feeder. Thus, the forward fault can be used for the SCEFR-
FLO block activation to disable wrong value calculation.
•
The delay (TONGAPC) must be set longer than the start delay of the directional
earth-fault function DEFLPDEF inside the terminal, but shorter than the minimum
operating time of the directional earth-fault functions in the substation. For example,
if the start delay is 100 ms and the shortest operating 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.
• Additionally, circuit breaker and disconnector status is used to verify thatentire
feeder is measured.
Figure 4.3-32 Typical configuration for triggering
Modeling a non-homogeneous line
A distribution feeder is built with several different types of overhead lines and cables.
This means that the feeder is electrically non-homogeneous. The nonhomogeneity can
be illustrated by drawing the protected feeder in an RX-diagram (in the impedance plane),
as shown in Figure 4.3-33. The impedance diagram is nonlinear.
typical_configuration_for_triggering.png
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