Firmware Design P54x/EN FD/La4
MiCOM P543, P544, P545 & P546
(FD) 9-15
FD
3.3 Platform software
The platform software has three main functions:
To control the logging of records that are generated by the protection software, including
alarms and event, fault, and maintenance records
To store and maintain a database of all of the relay’s settings in non-volatile memory
To provide the internal interface between the settings database and each of the relay’s
user interfaces, i.e. the front panel interface and the front and rear communication ports,
using whichever communication protocol has been specified (Courier, IEC 60870-5-103,
DNP 3.0)
3.3.1 Record logging
The log
ging function is provided to store all alarms, events, faults and maintenance records.
The records for all of these incidents are logged in battery backed-up SRAM in order to
provide a non-volatile log of what has happened. The relay maintains four logs: one each for
up to 96 alarms, 500 event records, 5 fault records and 5 maintenance records. The logs
are maintained such that the oldest record is overwritten with the newest record. The
logging function can be initiated from the protection software or the platform software is
responsible for logging of a maintenance record in the event of a relay failure. This includes
errors that have been detected by the platform software itself or error that are detected by
either the system services or the protection software function. See also the section on
supervision and diagnostics later in this chapter.
3.3.2 Settings database
The
settings database contains all of the settings and data for the relay, including the
protection, disturbance recorder and control & support settings. The settings are maintained
in non-volatile memory. The platform software’s management of the settings database
includes the responsibility of ensuring that only one user interface modifies the settings of
the database at any one time. This feature is employed to avoid conflict between different
parts of the software during a setting change. For changes to protection settings and
disturbance recorder settings, the platform software operates a ‘scratchpad’ in SRAM
memory. This allows a number of setting changes to be applied to the protection elements,
disturbance recorder and saved in the database in non-volatile memory. If a setting change
affects the protection & control task, the database advises it of the new values.
3.3.3 Database interface
The othe
r function of the platform software is to implement the relay’s internal interface
between the database and each of the relay’s user interfaces. The database of settings and
measurements must be accessible from all of the relay’s user interfaces to allow read and
modify operations. The platform software presents the data in the appropriate format for
each user interface.
3.4 Protection and control software
The protectio
n and control software task is responsible for processing all of the protection
elements and measurement functions of the relay. To achieve this it has to communicate
with both the system services software and the platform software as well as organize its own
operations. The protection software has the highest priority of any of the software tasks in
the relay in order to provide the fastest possible protection response. The protection &
control software has a supervisor task that controls the start-up of the task and deals with the
exchange of messages between the task and the platform software.
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