
The existence of the  benefits of the parallel transient stability analysis
program are based on the assumption that the program's output can be interpreted
and used for solving real time problem.  However, a typical run of transient
stability program generates huge amount of output data.  Since the program
will be sped up by at least an order of magnitude to solve real time problems,
the time available for the output analysis will be reduced accordingly.  As a
result, the engineer needs
some form of intelligent computerize aid to achieve the complex task of
understanding the transient stability program's output.
We propose to use a expert system program.

\begin{figure}
\psfig{figure=expert.eps,width=297pt,height=168pt}
\caption{Block digram for expert system program \label{expert-fig}}
\end{figure}

Expert systems have been under intense study by research organizations for
the last 10 years, and the
appearance success of expert systems is indicated by the 200 expert system
applications in over 30 companies~\cite{Expert-Survey}.
In addition, a experimental Transient Stability Expert system has been
implemented by~\cite{TSES} and the results are favorable.
The proposed expert system, as shown in figure~\ref{expert-fig},
will relieve most of the tedious task for the operator by filtering out
``obvious''
transient stable cases, reducing the amount of program output, which
requires human interpretation, and offering suggestions. Consequently,
the operator's productivity is enhanced.

The benefits of using such expert system are simplification of training,
minimization of human error and
time independent expert.  Since the expert system will partially
automate the information acquisition and data interpretation process, the
training of the operator
concentrates on correct response procedures, instead of, learning how
to use the various data acquisition and interpretation tools.  In addition,
the expert system
provides the operator with the accurate and concise ``big picture.''
The operator can then solve the existing problem with best available
information; hence, the chances of misjudgment is minimized.  The most
attractive advantage of the expert system is the time independent expertise.
The expert system is available on line as long as the computer remain in
operation.
Currently, the operation department is able to keep its computer in
operation for 96.8 percent of time.  The computer reliability will further
increase by the fault torrence of the parallel computer.  Therefore,
we can safely assume the expert system will be available all the time.
Even when emergency occurs on the time only junior stuff member is
on duty, the stuff member's decision is still backed by the expertise of
the expert
system.  Furthermore, the expert system can accumulate additional knowledge over
time.  Consequently, not only the quality of the operation control improves,
but it is also less
sensitive to the personnel fluctuation over the operation years of the expert
system.




