contacts. The subfunction for detecting a 3-phase measuring-voltage failure (see chapter 8.3.2.4 3-Phase
Measuring-Voltage Failure ) is not released in this situation, for example, because the current flow is too low.
This subfunction can be switched on or off separately using the Switch-on 3ph. failure parameter.
Application and Setting Notes
Parameter: Asym.fail. - time delay
•
Recommended setting value (_:113) Asym.fail. - time delay = 10.00 s
The Asym.fail. - time delay parameter allows you to set the time during which a system incident
detected after the occurrence of the unbalance resets the monitoring. This setting is important in the case of
weak infeed (current < 10 % of rated current) in order to give certain protection functions (such as distance
protection) more time for detecting system incidents. As long as the time delay runs, it is assumed that the
unbalance is due to a system incident.
As soon as the time has elapsed, the supervision assumes a measuring-voltage failure and seals in.
Siemens recommends using the default setting.
If you want the seal-in function to operate sooner or at once, you can reduce the time.
Parameter: Asym.fail.-DO on netw.flt.
•
Recommended setting value (_:115) Asym.fail.-DO on netw.flt. = No
Parameter Value Description
no
After elapse of the time delay the supervision function seals in. Even if the
system incident criterion is fulfilled, the protection functions concerned will
remain blocked.
This avoids an unselective tripping of the protection functions due to an
absence of the measuring voltage in the case of an unbalanced system inci-
dent.
This is the default setting.
yes
The seal-in function is switched off. The supervision drops out immediately
when a system incident is detected. With this setting, the unbalanced meas-
uring-voltage failure is only reported, and in the event of a double failure
(measuring-voltage failure and system incident in parallel), unselective trip-
ping is preferred.
Parameter: 3ph.fail. - VA,VB,VC <
•
Recommended setting value (_:101) 3ph.fail. - VA,VB,VC < = 5 V
The 3ph.fail. - VA,VB,VC < parameter allows you to set the pickup value of the monitoring.
Siemens recommends using the default setting.
If you expect major disturbances acting upon the voltage inputs, you can increase this value. Increasing the
values makes the supervision more sensitive to 3-phase system incidents.
Parameter: 3ph.fail. - phs.curr.release
•
Recommended setting value (_:102) 3ph.fail. - phs.curr.release = 0.1 A for I
rated
= 1 A or
0.5 A for I
rated
= 5 A
The 3ph.fail. - phs.curr.release parameter is used to define the phase current threshold above
which the monitoring is released.
Siemens recommends using the default setting.
Parameter: 3ph.fail. - phs.curr. jump
•
Recommended setting value (_:103) 3ph.fail. - phs.curr. jump = 0.1 A for I
rated
= 1 A or
0.5 A for I
rated
= 5 A
8.3.2.6
Supervision Functions
8.3 Supervision of the Secondary System
SIPROTEC 5, High-Voltage Bay Controller, Manual 943
C53000-G5040-C015-9, Edition 11.2017
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