An analytical approach for available transfer capability assessment

Expanding the extra high voltage transmission system and improving the transfer capability of the network are the primary tasks of the power network. With the increasing expansion transmission system scale, the super large scale network has taken shape. According to the definition of available transfer capability by North America Electric Reliability Council (NERC), we know that ATC not only depends on the topology of power network but also on the parameters of components. So a series of adequacy indices are proposed to evaluate ATC. The analytical expressions of these indices, with respect to component reliability parameters, are presented in this paper, and then the actual physical meanings of the coefficients in these analytical formulas are detailed. Based on these analytical formulas, a full set of sensitivity formulas of ATC adequacy indices with respect to component reliability parameters are deduced. Utilizing these analytical formulas, we can not only easily calculate the ATC adequacy indices accurately in an analytical mode when component reliability parameters vary, but also obtain the function curves of the ATC adequacy indices versus the component reliability parameters. Furthermore, using the analytical formulas we can effectively identify ATC bottlenecks and get important guide information for investment decision-making and maintenance. The algorithm based on MATLAB 6.5 is developed. The correctness and effectiveness of the proposed analytical approach for ATC assessment are verified using IEEE-RTS79 test system.