FACTS - DG Coordination in an Integrated Transmission & Distribution Network (IT & DN)

Abstract

To support improved performance and a sustainable power supply amid growing demand, modern power grids increasingly integrate Flexible AC Transmission Systems (FACTS) together with Distributed Generation (DG). However, planning studies often treat FACTS and DG independently, overlooking their mutual influence on system optimization. The work herein presents a bi-level optimization strategy designed to coordinate DG and FACTS for enhancing ATC, minimizing active losses, and reducing deviations in voltages. The methodology involves two optimizations: the Inner and Outer (IO and OO). The inner deploys a hybrid of the active flow Performance Index and PSO to plan Flexible AC Transmission Systems while Outer leverages Multiple objective variants of particle swarm optimization (MOPSO) to plan DG within a case study distribution network. The test network includes a distribution and transmission components, specifically using the Western Systems Coordinating Council's 9-bus system and the IEEE 16-node model. PV and PQ DG models are synchronized with two types of FACTS, TCSC and SSSC. Findings indicate notable ATC improvements, particularly with TCSC - PQDG and SSSC - PQDG combinations, and the Pareto front curves reveal a non-linear trend, where ATC gains plateau beyond a certain maximum value as the Pareto slope nears zero.