remote control equipment - Indian Railways Institute of Electrical ...

Just as the requirements of supervisory control system years ago were rather simple,
so were many of the tecniques employed Naturally, as the scope of the supervisory control
applications changed, so did many of the fundamentals of supervisory conrols technology.
Coding patterns were improved to provide higher security and more efficiency. Communication
tecniques were changed to permit higher speeds of transmission. The advent of solid state
circuitry opened vast new possibilities in both operation and capabilities.
7.2.1 WHAT IS SUPERVISORY CONTROL?
Supervisory Control is a collection that will provide an operator, at a remote location,
with enough information to determine the status of a substation or generating station and to
cause actions or operations to take place at that station without being physically present.
Although a supervisory control system may exist to perform control and data acquisition at one
specific location, the normal arrangement is to have one central location receiving data and
exercising control over many remote stations
7.2.2 WHY INSTALL SUPERVISORY CONTROL?
The usual reason for installing supervisory control systems is to provide the system
operators with sufficient information and control to operate the power system, or some part of
it, in a safe, secure and economical manner. Before taking decision to install a SCADA
system, certain factors are to be clearly defined. These factors are as follows :-
7.2.2.1 Who are users of data?
In a typical case, the user can be Operators for controlling the system, Maintenance
deparment for maintaining the power supply equipment, Management for decision making and
System Designer for designing a better system.
7.2.2.2 What data is available and/or neccessary?
As theoretically it is possible to gather data pertaining to each and every event or
activity on the power system, a judicial balance has to be kept between available finances as
well as identification of all potential users and there requirements.
7.2.2.3 What are the user requrements?
As the SCADA is being designed for the use of power system operators, their needs
have to be serviced first.
Firstly, the operator requires only that data, which will quickly and positively alert him to
a problem and give ‘him the means to take corrective action in a timely manner. So a sort of
filter has to be built in the system to isolate and present the useful data only, to the operator.
Then the data has to be in real time for the operator. Almost all other users have a need of
the data for carrying out some postmortem operations. This imposes a time constraint on the
system for collecting and reporting of data.
Second important need is orgainsed presentation of the data, which should be made available
for which the size of bulk memory has to be fixed.
Thirdly, means to get hard copy of data in a chronological order should be made available, for
which the size of bulk memory has to be fixed.
And lastly, feature for getting summary of varous events/records should be possible.
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