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\centerline{\bf \huge The Niagara Mohawk Project:}
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\centerline{\bf \LARGE Parallel Processing for Power Utility Applications}
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\bigskip
\centerline{\large Geoffrey Fox, Paul Coddington,}
\medskip
\centerline{\large Sanjay Ranka, Alok Choudhary,} 
\medskip
\centerline{\large Dave Koester, Alvin Leung, Kamala Anupindi,}
\medskip
\centerline{\large Mike Nilan, Salim Hariri} 
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\bigskip
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{\large
\noindent
The proposed project with Niagara Mohawk Power Corporation involves the
following activities:

\begin{itemize}
\item  Development of parallel algorithms for certain areas of power
       network simulation
\item  Investigation of new numerical algorithms for solving power
       network equations
\item  Development of a user interface and expert system to help 
       system operators to rapidly interpret the simulation data 
\item  Comparing the performance of the software on different parallel
       computers, and making recommendations for appropriate hardware  
\item  Finding commercial partners and funding for the development
       of a commercial software product 
\item  A survey of the applicability of High Performance Computing 
       and parallel processing to the utility industry
\end{itemize}
}

\newpage

\centerline{\bf \LARGE Power Network Simulation}

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{\large

\noindent
The Niagara Mohawk power network has on the order of 
\begin{itemize}
\item  300 generators 
\item  2000 buses (network nodes)
\item  8000 transmission lines (network connections)
\end{itemize}
This is dependent on various approximations (high or medium voltage
components, effect of connections outside of the NiMo network, etc.)

\bigskip
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\noindent
Remote telemetry units provide data on the state of the network every 
few seconds. This data is used as input to network simulation software 
which performs the following tasks:
\begin{itemize}
\item  {\bf load flow analysis} -- calculate the current state of the network
\item  {\bf network planning} -- calculate effects of changes to the network
\item  {\bf unit commitment} -- estimate future demand and the most economic
       use of generation capacity to provide for this demand
\item  {\bf contingency evaluation} -- simulate the ability of the network
       to cope with component failures
\item  {\bf transient stability analysis} -- analyze the synchronization 
       stability and of generators following a component failure
\end{itemize}

\bigskip
\noindent
Our project will concentrate on methods of improving contingency evaluation,
transient stability analysis, and unit commitment simulations, by using
new algorithms and high performance parallel computing. 

\medskip
\noindent
Current simulations are limited in both accuracy and frequency by the
available computing resources (currently IBM mainframes).
NiMo would like to be able to use better approximations and do near
real-time simulation. 

}
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\centerline{\bf \LARGE Contingency Evaluation}

{\large

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\noindent
NiMo Operations group has a list of around 200 ``contingencies'', \\
i.e. possible network component failures, or components removed
for maintenance. 

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\noindent
The effect of these contingencies is evaluated periodically (every 
few minutes) using current data. 

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\noindent
The network must be able to cope with these contingencies, which 
requires:
\begin{itemize}
\item  Extra generation capacity or ``spinning reserve'' \\
       (since it takes a long time to bring a new generator on-line, 
       must have generators turning but not producing power)
\item  Extra transmission capability \\
       (ability to reroute power)
\item  Avoiding cascading failures \\
       (i.e. failure in one component causing
       overload and failure in another component, etc. etc.)
\end{itemize}

\bigskip
\noindent
Network reliability is an important problem:
\begin{itemize}
\item  As many as 35 serious power interruptions per year in the USA
\item  The Great Blackout of 1965
       \begin{itemize}
       \item  cascading failures disrupted Northeast power grid
       \item  30 million people affected
       \item  destroyed an expensive generator
       \end{itemize}
\end{itemize}

\bigskip
\noindent
Current contingency evaluation programs make a number of simplifying
assumptions, most notably ignoring transient effects. 


}
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\centerline{\bf \LARGE Transient Stability Analysis}

{\large

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\noindent
Transient stability analysis (TSA) is currently done only in the network 
planning stage. Contingency evaluation uses a simple approximation.

\bigskip
\noindent
The lack of accurate simulations requires conservative operating
margins. Accurate, near real-time contingency evaluation incorporating
TSA would:
\begin{itemize}
\item  Reduce wasted energy from excess spinning reserve
\item  Reduce environmental impact
\item  Improve system reliability
\item  Reduce costs by perhaps as much as \$1M per year 
\end{itemize}

\bigskip
\noindent
Current output of TSA program is a complicated function for each 
generator, which must be interpreted by a trained engineer. 
To incorporate TSA into near real-time contingency evaluation, need to:
\begin{itemize}
\item  Construct an expert system to filter output data 
\item  Improve user interface to help operators interpret the output
\item  Improve algorithms for solving network equations
\item  Reduce simulation time in a cost effective manner by using 
       parallel processing 
\item  Create efficient parallel algorithms
\item  Merge contingency evaluation software (STAG) with TSA
       software (PTI) and new NPAC software
\end{itemize}

}
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\centerline{\bf \LARGE Solving the Network Equations}

{\large

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\noindent
\leftmargini=0pt
\begin{itemize}
\item {\bf Network Equations} \\
      The network (nodes and connections) can be described by algebraic
      equations, which can be represented as large, sparse matrices:
      \begin{itemize}
      \item Large: $N \times N$ matrices, where $N$ = number of nodes.
      \item Sparse: number of non-zero elements = number of connections.
      \end{itemize}
\item {\bf Generator Equations} \\
      The dynamics of the generators are described by non-linear 
      differential equations.
\item {\bf Differential-Algebraic Equations (DAEs)} \\
      The total system is described by a combination of differential and 
      algebraic equations, which can also be converted into matrix form.
\item {\bf DAE Solvers} \\
      DAEs are used in many other fields such as structural 
      mechanics and chemical engineering. Newly developed DAE solvers 
      could improve the simulation of power networks. 
\item {\bf Sparse Matrix Solvers} \\
      All the DAE solvers require the solution of sparse matrix equations,
      which use different algorithms to standard (dense) matrix problems.
\item {\bf Parallel Algorithms} \\
      \begin{itemize}
      \item Some Parallel DAE solvers have been implemented, need to find the
            best one for this application. 
      \item Parallel computers are good at solving dense matrix problems,
	    but not so good at sparse matrices, unless they have some regular
	    structure. Type of algorithm used depends on the structure -- 
	    general solvers usually not the most efficient.
      \item Power network equations have a specific structure, and we are
            developing new parallel algorithms to exploit this structure.
      \end{itemize}
\end{itemize}

}
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\centerline{\bf \LARGE Other Work}

{\large

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\noindent
\leftmargini=0pt
\begin{itemize}
\item {\bf User Interface and Expert System} 
      \begin{itemize}
      \item  Need to work closely with NiMo operators and engineers
	     on user requirements and rules for expert system
      \item  Nilan and Hariri have experience in previous work for NiMo
      \end{itemize}
\bigskip
\item {\bf Unit Commitment} 
      \begin{itemize}
      \item Build on previous work by Dave Koester on shared memory parallel 
	    algorithms 
      \item Port to distributed memory, improve efficiencies 
      \item Improve optimization techniques 
      \end{itemize}
\bigskip
\item {\bf Survey of HPC Applications} \\
      \smallskip
      Possible applications include:
      \begin{itemize}
      \item Customer databases
      \item Simulation of nuclear power stations
      \item Natural gas distribution
      \item Others to be investigated
      \end{itemize}
      General surveys of this kind have been done by other groups, 
      but have not concentrated on crucial software issues.  \\
      \smallskip
      We will also look at applications important to NiMo.
\end{itemize}

}


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