High-pulse-count rectifier systems (with more than six pulses) are often used in high-power applications. Dynamic average value modeling (AVM) has proven to be indispensable for simulation and analysis of such power electronic systems. However, developing accurate AVMs for such line-commutated converters is challenging due to the presence of complicated switching patterns (operating modes), configuration of multi-phase transformers and/or rotating machines, inter-phase transformers, filters, etc. This paper presents a generalized methodology for full-order dynamic average modeling of high-pulse-count line-commutated rectifiers, which is based on the recently proposed parametric AVM approach. Extensive simulation studies are carried out considering the 18-pulse rectifier example system. The accuracy and numerical advantages of the developed generalized AVM is verified against the detailed switching model, and a previously established average model in time and frequency domains.