A streamlined and enhanced iterative method for analysing power system available transfer capability and security

Abstract

Available Transfer Capability (ATC) is a crucial indicator for ensuring the reliable and efficient electric grid as it helps to manage congestion and ensure that the power flows are kept within safe operating limits. This article presents a novel approach named as modified repeated alternating current power flow (MRACPF) with step-size control mechanism and compares it with the existing techniques like direct current power transfer distribution factors (DCPTDF) and repeated alternating current power flow (RACPF) for analyzing the ATC of the power system during bilateral wheeling transactions in MATLAB environment. The study further assesses the ATC in different multilateral wheeling transactions of two standard test systems (IEEE 30-bus and IEEE 118-bus) and evaluates inter-area ATCs for the IEEE 118-bus system under various operational scenarios. The Composite Security Index (CSI) which is based on both line flow limit and bus voltage limit violations is used to identify and rank the most severe (k-1) line contingencies, and is able to differentiate between secure and insecure state of the power system and furthermore, MRACPF with step-size control mechanism is used to assess ATC during the severe (k-1) line outage and generator outage scenarios for various power transactions. The MRACPF method produces comparable results to the RACPF method for obtaining the Available Transfer Capability (ATC), but it takes less time. This time savings can be significant, especially for larger power systems, where the execution time can be reduced by more than 50%.