Siemens siprotec 7SA522 - Setting Notes

2.9.2 Tripping According to French Specification
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7SA522 Manual
C53000-G1176-C155-3
2.9.1.2 Setting Notes
General It is a prerequisite for the operation of the weak infeed function that it was enabled
during the configuration of the device at address  :HDN,QIHHG = (QDEOHG.
With the parameter )&7:HDN,QIHHG (address ) it is determined whether the
device shall trip during a weak infeed condition or not. With the setting (&+2DQG
75,3 both the echo function and the weak infeed tripping function are activated. With
the setting (&+2RQO\ the echo function for provision of the release signal at the in-
feeding line end is activated. There is however no tripping at the line end with missing
or weak infeed condition. As the weak-infeed measures are dependent on the signal
reception from the opposite line end, they only make sense if the protection is coordi-
nated with teleprotection (refer to Section 2.6 and/or 2.8).
The receive signal is a functional component of the trip condition. Accordingly, the
weak infeed tripping function must not be used with the blocking schemes. It is only
permissible with the permissive schemes and the comparison schemes with release
signals! In all other cases it should be switched 2)) at address . In such cases
it is better to disable this function from the onset by setting address  to 'LVDEOHG
during the device configuration. The associated parameters are then not accessible.
The undervoltage setting value 81'(592/7$*( (address ) must in any event be
set below the minimum expected operational phase–earth voltage. The lower limit for
this setting is given by the maximum expected voltage drop at the relay location on the
weak-infeed side during a short-circuit on the protected feeder for which the distance
protection may no longer pick up.
The remaining settings apply to the echo function and are described in the corre-
sponding sections (2.6 or 2.8).
2.9.2 Tripping According to French Specification
2.9.2.1 Method of Operation
An alternative for detecting weak infeed is only available in the models 7SA522*-**D**.
Pickup with Rela-
t i v e Vo l t a g e J u m p
In addition to the classical function of weak infeed the so-called /RJLFQR (ad-
dress ) presents an alternative to the method used so far.
This function operates independently of the teleprotection scheme by using its own
receive signal and it is able to trip with delay and without delay.