A Modified IEEE 118-Bus Test Case for Geomagnetic Disturbance Studies–Part I: Model Data

Power grid test cases for geomagnetic disturbance (GMD) studies need particular data that are not provided by the typical IEEE transmission benchmarks. This two-part paper proposes a test case that contains required modeling details for time-domain simulation of a GMD within an electromagnetic transient program (EMT-type). Compared to existing load-flow-based GMD test cases, the proposed test case offers advantages, such as accurate representation of nonlinear transformer magnetization and interaction between the dc geomagnetically-induced currents and transformer saturation, additional var consumption, harmonics, and voltage regulation problems. Part I presents the test case system and parameter data, and Part II provides simulation results to enable software-to-software validation (future work) as a first step toward the establishment of the model as an official GMD benchmark.