P54x/EN FD/La4 Firmware Design
(FD) 9-18
MiCOM P543, P544, P545 & P546
FD
The execution of the PSL logic is event driven; the logic is processed whenever any of its
inputs change, for example as a result of a change in one of the digital input signals or a trip
output from a protection element. Also, only the part of the PSL logic that is affected by the
particular input change that has occurred is processed. This reduces the amount of
processing time that is used by the PSL. The protection and control software updates the
logic delay timers and checks for a change in the PSL input signals every time it runs.
This system provides flexibility for the user to create their own scheme logic design.
However, it also means that the PSL can be configured into a very complex system, and
because of this setting of the PSL is implemented through the PC support package MiCOM
S1 Studio.
3.4.4.1 PSL data - attaching a text identifier for version traceability
In the PSL editor in MiCO
M S1 Studio when a PSL file is downloaded to the relay the user
can specify the group to download the file and a 32 character PSL reference description.
This PSL reference is shown in the ‘Grp1/2/3/4 PSL Ref’ cell in the ‘PSL DATA’ menu in the
relay. The download date and time and file checksum for each groups PSL file is also
shown in the ‘PSL DATA’ menu in cells ‘Date/Time’ and ‘Grp 1/2/3/4 PSL ID’. The PSL data
can be used to indicate if a PSL has been changed and thus be useful in providing
information for version control of PSL files.
The default PSL Reference description is “Default PSL” followed by the model number e.g.
“Default PSL P54x??????0yy0?” refers to the software version e.g. 40. This is the same for
all protection setting groups (since the default PSL is the same for all groups). Since the
LCD display (bottom line) only has space for 16 characters the display must be scrolled to
see all 32 characters of the PSL Reference description.
The default date and time is the date and time when the defaults were loaded from flash into
EEPROM.
Note: The PSL DATA column information is visible via the relay front panel
interface or over the Courier communications protocol.
3.4.5 Event recording
A chang
e in any digital input signal or protection element output signal causes an event
record to be created. These events are generated by the relay protection software and
immediately time stamped before being buffered in a fast area of memory to avoid
compromising the protection function of the relay. They are then transferred to battery
backed up SRAM for non-volatile storage. It is possible for the fast buffer to overflow under
avalanche conditions, if this occurs then a maintenance record is generated to indicate this
loss of information.
3.4.6 Disturbance recorder
The
disturbance recorder operates as a separate task from the protection and control task.
It can record the waveforms for up to 12 calibrated analog channels and the values of up to
32 digital signals. The recording time is user selectable. Up to 50 seconds of data can be
recorded. A minimum number of 5 records with a capacity of 10 seconds each, up to a
maximum of 50 records with a capacity of 10 seconds each can be set. The disturbance
recorder is supplied with data by the protection and control task once per cycle. The
disturbance recorder collates the data that it receives into the required length disturbance
record. The disturbance records can be extracted by MiCOM S1 Studio which can also store
the data in COMTRADE format, therefore allowing the use of other packages to view the
recorded data.
3.4.7 Fault locator
The fault lo
cator locator uses a 12-cycle buffer of the analog input signals and returns the
calculated location of the fault to the protection and control task which includes it in the fault
record for the fault. The prefault and fault voltages and currents are calculated by the fault
locator, there are also presented within the fault record. When the fault record is complete
(i.e. includes the fault location), the protection and control task can send a message to the
supervisor task to log the fault record.
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