The Challenge 1 Output Files and Format description is in Appendix E of the Problem Formulation.
Two files need to be produced in order for a submission to be scored:
solution1.[txt | hdf5] consists of three sections (bus voltage, generator power output, and switched shunt admittance) that contain the power system base case operating point as determined during the timed portion of the solution algorithm.
solution2.[txt | hdf5] consists of information for each contingency in four sections (contingency bus voltage, contingency generator power output, contingency switched shunt admittance, and contingency area delta) that contain the results from the power flow analysis.
The data should be written with the full numerical precision in which the solution was generated to avoid feasibility issues resulting from rounding errors.