Performance comparison of two exact outage simulation techniques

The paper compares the performance of two exact load-flow and outage simulation techniques. The second-order Newton-Raphson technique is described first, where the voltages are represented in rectangular co-ordinates. Then the power-flow solution by the method of reduction and restoration is described. Both methods use the complete Taylor series expansion of the nodal equations but the latter is different in that (a) only voltage-controlled busbars are retained during the iterative process, (b) a smaller-order Jacobian is used, and (c) on convergence the system is restored to the original size. Outages are simulated using the current injection principle for both techniques. The advantages and disadvantages of both are discussed.