Record Logging; Settings Database; Database Interface; Protection And Control Software - GE P741 Technical Manual

Firmware Design
MiCOM P741, P742, P743
3.4 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 or IEC 60870-5-
103).
3.4.1

Record logging

The logging 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 32 alarms, 512 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 document (P74x/EN FD).
3.4.2

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. (See also the
Introduction to this manual (P74x/EN IT) on the user interface). If a setting change affects
the protection & control task, the database advises it of the new values.
3.4.3

Database interface

The other 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.
3.5

Protection and control software

The protection 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.
P74x/EN FD/Na7
(FD) 9-21
FD