The need for accelerating power grid simulation through high performance computing (HPC) has long been recognized, and prior efforts have been devoted to developing one-off parallel computing applications for particular power grid functions. Non-transferable software codes and duplicated implementations in these prior efforts are a major barrier to more widespread HPC adoption in power grid applications. Modern HPC hardware and architecture require significant computing expertise for application development. The GridPACK (TM) software framework described in this paper provides an HPC-compatible software structure to access modern parallel solvers and HPC-ready modules for common components in power grid simulation applications. GridPACK hides the HPC details and enables power system developers to focus on applications instead of computational details. Several example applications of GridPACK are presented to demonstrate the capabilities of GridPACK and the performance of HPC simulations with large power grid networks. Examples discussed include: a dynamic simulation application capable of running a 17,156-bus Western Electricity Coordinating Council (WECC) system in a computational speed faster than real time (e.g., under 30 s for a 30-s simulation), a static contingency analysis application using a task manager, and a dynamic contingency analysis application utilizing two levels of parallelism. These example applications illustrate GridPACK's capabilities to support different types of simulations within a unified framework and. to support reuse of transferable software codes across power grid applications. The computational results indicate strong performance improvements for power grid simulations with GridPACK. (C) 2016 Elsevier B.V. All rights reserved.