Reliability impact of dynamic thermal rating on power system under high wind penetration and frequency security constraints

With the increasing integration of wind energy into modern power systems, challenges related to frequency security, transmission congestion and overall system reliability have become increasingly critical. This paper investigates the application of Dynamic Thermal Rating (DTR) technology as a potential solution to mitigate challenges associated with high wind power penetration and frequency security constraints. A modified low-order Aggregated System Frequency Response (ASFR) model is developed to analyze frequency dynamics under different levels of wind power penetration. The integration of wind power is limited by system frequency constraints, which subsequently affect system reliability. To address these issues, the reliability performance of a modified IEEE 24-bus test system integrated with DTR is first assessed, and the scalability of the proposed framework is subsequently validated on an extended IEEE RTS-96 system. Under high-load conditions and at 30 % wind power penetration, the inclusion of the ASFR model to represent frequency security constraints reduces the Expected Energy Not Supplied (EENS) mitigation benefit of DTR by 19.7 %. The results indicate that neglecting frequency security constraints may lead to an overestimation of the reliability benefits attributed to DTR. To evaluate system performance under different conditions, four representative scenarios are considered with wind power penetration levels ranging from 20 % to 50 %. These scenarios incorporate strategies such as curtailment, synthetic inertia, de-loaded operation and energy storage system integration. The results demonstrate that DTR plays a critical role in enhancing the integration of renewable energy sources while maintaining system reliability and operational security under varying load and frequency conditions.