Iterative Clearing Model and Method for Electricity Spot Market with Embedded Direct Current Power Flow Security Check

The effective operation of the electricity spot market relies on efficient market clearing methodologies. The Security-Constrained Unit Commitment (SCUC) program is the core of the clearing process. With the gradual increase in the number of market participants in the spot market and the consideration of more grid sections, the extremely dense matrix formed by transmission constraints and a large number of market participants poses significant challenges to the spot market clearing. To address this, an iterative clearing mechanism incorporating embedded Direct Current (DC) power flow security check and linearized Alternating Current (AC) power flow constraints has been established. This mechanism includes an optimization phase without network constraints and a DC power flow security check based on full data sensitivity, which rapidly provides initial schedules and grid power flows for optimized clearing. On the basis of security check result, the market clearing employs an incremental power flow method based on filtered sensitivity, improving iterative efficiency and the accuracy of power flow calculations during clearing. Through simulation analysis, the effectiveness of the proposed iterative clearing method has been validated, and this clearing method has already been implemented in practical provincial-level spot markets in China.