Impact of Load Variation and Generation contingency on Available Transfer Capability

The deregulation of power systems has enhanced competition and efficiency within electricity markets. However, the reliance on shared transmission networks introduces challenges related to congestion and system stability, making the assessment of Available Transfer Capability (ATC) essential for ensuring secure power transfers. ATC represents the maximum permissible power transfer without violating thermal, voltage, or stability constraints. Its calculation is highly sensitive to changes in load distribution, network topology, and contingency conditions. This study investigates the influence of load variations, generation dispatch shifts, and contingency events on ATC using a sensitivity-based approach implemented in PowerWorld Simulator. A detailed five-bus power system model is employed to evaluate ATC under varying sink bus loads and generator configurations. Additionally, N-1 contingency analysis is conducted to quantify ATC reduction resulting from outages of transmission lines and generating units. The results reveal a significant decline in ATC with increasing load demand, generator outages, and binding transmission constraints, highlighting the need for robust transmission planning and effective congestion management. This study underscores the importance of real-time ATC assessment and optimization techniques for system operators, market participants, and policymakers. The proposed methodology is scalable and applicable to larger power systems, contributing to improved grid reliability and operational planning.