Impact of Commutation Failure Preventions on HVDC System Based on a Multi-Index Value Set Approach

This paper proposes a systematic method, based on rational approximation and value set approach, to unravel the impact of commutation failure preventions (CFPREVs) on HVDC system dynamics. First, some output variables in HVDC system dynamics are identified as performance indices, it is shown that these indices are rational functions of CFPREVs parameters. Then a numerical approximation method is used to determine the coefficients of the rational functions which describe the analytical relationship between the suggested performance indices and parameters. To help understand the connotation of the obtained expressions, a multi-index value set approach, which exploits the power of geometry and graphics, is described in detail. Finally, the results of the rational approximation and value set approach are reported.