Dynamic Transmission Capability Calculation Using Integrated Analysis Tools and Intelligent Systems

This paper presents a methodology to calculate the transmission capability between two areas in a power system, considering both static and dynamic security assessment. An optimal power flow (OPF) algorithm is used to compute the transmission capability from the static point of view. The dynamic security assessment of the operating point obtained from the OPF is then evaluated. Transient, voltage, and small-signal stability assessment are considered. If any dynamic security criterion is violated, additional constraints are added to the original OPF formulation, and a new and secure transmission limit is calculated. These new constraints can be very simple, such as to limit the transmitted power, or more elaborated, based on some rules obtained from an intelligent system. The intelligent system adopted is a fuzzy inference system (FIS) that drives the redispatch of the active power generation. The FIS output is used to formulate the new constraints to the OPF. In addition to the OPF, the proposed methodology makes use of other power systems analysis tools, such as full time-domain simulation, fast simulation, and modal analysis. The methodology was implemented in a computational platform that integrates all these tools in a single framework. The results for two test systems have shown the potential benefits of the proposed methodology and the importance of considering different dynamic aspects in transmission capability calculation.