All the data and parameters used for the paper entitled "Capturing Chronology and Extreme Values of Representative Days for Planning of Transmission Lines and Long-Term Energy Storage Systems", https://doi.org/10.1109/PowerTech55446.2023.10202993, are uploaded as an Excel file (Modified_6-bus_System). The provided file is straightforward to understand. For using this file, the only point that is required to be mentioned is as follows: The sheets' names are the same as the utilized definitions in the paper. For example, matrix "A" is the same in Excel file and paper formulations.