Method of operation7SV512
V1
38
C53000---G1176---C91
The fault inception is indicated with the absolute
time of the operating system. The sequence of the
events istagged with the relative time referred tothe
moment at which the fault detector has picked up.
Thus, the elapsed time until tripping is initiated and
until the tripsignal isreset canbe readout. The reso-
lution is 1 ms.
The events can also be read out with a personal
computer by means of the appropriate program
DIGSI. This provides the comfort of a CRT screen
and menu-guided operation. Additionally, the data
can be documented on a printer or stored on a
floppy disc for evaluation elsewhere.
The protection device stores the data of the last
three network faults; ifafourthfault occurstheoldest
fault is overwritten in the fault memory.
Anetwork fault begins withrecognition ofthe fault by
pick-up and ends with fault detector reset.
4.5.1.3 Information to a central unit (optional)
All stored information can be transmitted via an opti-
cal fibre connector (optional) to a control centre, for
example, the SIEMENS Localized Substation Auto-
mation System LSA 678. Transmission uses a stan-
dardized transmission protocol according to DIN
19244.
4.5.2 Data storage and transmission
for fault recording
The instantaneous values of the measured values
i
L1
, i
L2
, i
L3
, i
E
are sampled at 1 ms intervals (for50 Hz) and stored
in a circulating shift register. In case of a fault, the
data from 5 cycles before the occurrence ofthe fault
up until 5cycles after theend of the network fault are
stored, max. over 3 seconds. These data are then
available for fault analysis. For each renewed net-
work fault, the actual new fault data are stored with-
out acknowledgement of the old data.
Thedata canbetransferred toaconnected personal
computer via the operation interface at the frontand
evaluated bytheprotection data evaluation program
DIGSI. The currents are referred to their maximum
values, normalized to their rated values and pre-
pared for graphic visualization. In addition, the sig-
nals ”Pick-up”, ”Trip” and ”Drop-off” are marked on
the fault record.
Alternatively, the fault record data can be trans-
mitted to a control centre via the serial interface (if
fitted). In this case data are stored from3periods be-
foreto30periods afterpick-up ofthe device.Evalua-
tion of the data is made in the control centre, using
appropriate software programs. The currents arere-
ferred to their maximum values, normalized to their
rated values and prepared for graphic visualization.
In addition, the signals ”Pick-up”, ”Trip” and ”Drop-
off” are marked on the fault record.
When the data are transferred to a central unit, read-
out can proceed automatically, optionally after each
pick-up of the relay or after an instantaneous trip.
The following then applies:
--- The relay signals the availability of fault record
data,
--- The data remain available for recall until com-
mencement of the next fault event.
--- A transmission in progress can be aborted by the
central unit.
4.5.3 Operating measurements and
conversion
For local recall or transmission of data, the true rms
values of the measured currents are always avail-
able.
The following is valid:
---I
L1,
I
L2,
I
L3
Phase currents in amps primary and
in % of rated current
---I
E
Earth current in amps primary and
in % of rated current
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