PSS®E is the premier software tool used by electrical transmission participants world-wide. The probabilistic analyses and advanced dynamics modeling capabilities included in PSS®E provide transmission planning and operations engineers a broad range of methodologies for use in the design and operation of reliable networks. PSS®E is the standard Siemens offering for electrical transmission analysis that continues to be the technology of choice in an ever-growing market that exceeds 115 countries. Since its introduction in 1976, the Power System Simulator for Engineering tool has become the most comprehensive, technically advanced, and widely used commercial program of its type. It is widely recognized as the most fully featured, time-tested and best performing commercial program available. PSS®E is an integrated, interactive program for simulating, analyzing, and optimizing power system performance. It provides the user with the most advanced and proven methods in many technical areas, including: Power Flow Optimal Power Flow Balanced or Unbalanced Fault Analysis Dynamic Simulation Extended Term Dynamic Simulation Open Access and Pricing Transfer Limit Analysis Network Reduction