The existing methods for the simulation of GMD effects in transformers and power systems are based on different approaches. The prominent techniques are analytical methods, time-domain simulation, phasor-based analysis, and FEM methods. These methods are currently used in the academic research as well as the commercial tools to address the industrial needs. The purpose of this panel is to discuss the challenges that these methods are facing with and identify the road map for future research and improvement in this field. This session will also review the state-of-the art of tools and simulation techniques related to the analysis and simulation of geomagnetic disturbances (GMD). Interest and efforts in this area have grown significantly in response to NERC reliability standard TPL-007. Some of the areas to be covered include earth impedance modeling (e.g., 1D, 3D, coastal effects), transformers, simulation techniques required for compliance with the NERC GMD standards.