T/JES 017-2026 Technical Requirements for Carbon Emission Reduction Accounting for AC Lines Conversion to Embedded DC

Scope

The core technical content of the standard is to provide a complete set of carbon emission reduction accounting methods for the transformation of AC power grids into embedded DC projects. The standard clarifies the various technical elements required for accounting, including: the project boundary should include DC lines and directly connected converter stations and other facilities; the method for determining the start and end time of the project accounting period; and the clear specification that only carbon dioxide is used as the main greenhouse gas type for accounting. The standard stipulates that the baseline scenario should be a situation where AC lines in the project area are replaced by DC lines for transmission, and exempts such projects from additional justification. The core technology lies in the calculation of baseline emissions and project emissions, which is based on accurately accounting for transmission losses in the two scenarios. The project emissions need to calculate technical losses, which are the sum of DC line losses and converter station losses. All calculations rely on the monitoring and acquisition of a series of key parameters, including: system input power, regional grid carbon dioxide emission factors, load curves, power factors, and converter station losses. To ensure the accuracy of the results, the standard requires that the transmission losses in the baseline scenario must be simulated using internationally recognized power system analysis software (such as those compliant with IEC and ANSI standards) and recommends using Newton-Raphson or Gauss-Seidel algorithms for power flow studies. The input parameters required for the simulation, such as the voltage level, length, inductance coefficient, and capacitance coefficient of the baseline lines, must come from certified project design documents. The entire simulation process and results must be confirmed by third-party certified engineers. In addition, the standard sets stric

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