.PowerGrids.Types.Choices.TimeConstantsApproximation .PowerGrids.Types.Choices.TimeConstantsApproximationtype TimeConstantsApproximation = enumeration(classicalDefinition "Tpd0 = T1, Tppd0 = T3", accurateEstimation "Tpd0 = T1+T2, Tppd0 = T1T3/(T1+T2)", exactComputation "Exact polynomial roots");