This paper presents an efficient approach for modeling irregular shaped power distribution networks (PDN) in high-speed packages. The proposed methodology is based on discretization of the plane into an orthogonal grid of transmission line segments. Using a delay-extraction-based model for each line segment, a compact circuit model is achieved where the size of the circuit matrices depend only on the nodes of the orthogonally discretized structure and all other internal nodes due to the macromodel are eliminated. This approach of eliminating the internal variable due to the transmission line macromodel is further extended to model skin effect losses without augmenting the circuit matrices. The proposed work has been successfully implemented for a variety of PDN structures and geometries and has been shown to yield significant savings in memory and run time costs compared to the existing simulation program with integrated circuits emphasis macromodels.