Real-Time Power Market Clearing Model with Improved Network Constraints Considering PTDF Correction and Fast-Calculated Dynamic Line Rating

The increasing penetration of renewables in power systems reconfigures the generation mix and geography distribution, resulting in more frequent power flow congestion. Conventionally, a relatively conservative dispatch margin for transmission congestion in network constraints was reserved to ensure safe operation due to potential deviations introduced by DC power flow modeling and conservative line rating. This paper proposes a real-time power market clearing model with improved network constraints considering power transfer distribution factor (PTDF) correction and fast-calculated dynamic line rating. The clearing model based on PTDF correction is proposed first employing the Taylor expansion with the voltage and phase angle approximation. An improved dynamic line rating model is further applied into the clearing model based on the piecewise linear approximation method, which calculates real-time conductor temperature faster with sufficient precision. We test and verify the validity of the proposed model based on three independent systems including the IEEE 39-bus system, the IEEE 2383-bus system, and the real power grid system in Yunnan province of China, respectively. The results show that the improved clearing model reduces the calculated power flow deviation between the clearing results and real conditions compared with traditional security constraints, where the efficiency of power grid operation is also increased.