This paper presents a comprehensive survey on application of various conventional, optimization and artificial intelligence (AI) based computational techniques for impact assessment of optimally placed and coordinated control of distributed generations (DGs) and flexible AC transmission systems (FACTS) controllers in power systems (PSs). This review work is presented from the viewpoint of different performance criterion enhancement of PSs such as minimization of active and reactive power losses and reduction of cost of system, more flexible operation and control, increase overall system energy efficiency, increase reliability of system, relieved transmission and distribution congestion, enhance power quality (PQ) of system, improve the voltage profile (VP), increase the loadability of systems, increase available power transfer capacity (APTC) of system, enhance PS stability, reduce PS oscillations, improve environmental GHG conditions and provide the reactive power support in emergency case such as under fault, sudden change in field excitation of alternators or load increase in PSs. This paper also presents the current status of the various conventional, optimization, and AI computational techniques for optimally placed and coordinated control of DG and FACTS controllers in PSs for enhancement of PSs performance parameters. Authors strongly believe that this survey will be very much useful to the researchers, scientific engineers, industrial persons working in this area to find out the relevant references and current state of the art.
