FACTS controller integration in AC/DC network for stability improvement

This paper evaluates the effectiveness of FACTS controller in AC/DC network stability improvements during operational change offered at the interface bus. In general, HVDC links have been used since decades for long distance bulk power transmission and asynchronous interconnections. However, the expansion of load and generation at respective converter station domain keep on changing due to both industrial and population growth, this may result in inadequate converter control behaviour and lead to either connecting AC system stability or converter control operational stability deterioration. Advance converter control technology has been proved successful for various changes offered dynamically, but in case of sudden fault or loss of generator the area may experience undesirable oscillations and may affect converter operation resulting in tripping of converter station. Since converters alone cannot compensate the sudden reactive power requirement due to its own control limitation, this may be viewed as operationally challenging scenario. In open access, as many HVDC links are connected in close proximity, disturbance in one link may introduce oscillation in other connected links and deteriorate the performance of the entire network. STATCOM integration in network has been found better not only for stability but also life extension of both switchyard equipments and controllers deployed. The concept has been demonstrated with study of sample system model represented in PSCAD/EMTDC environment. The analysis provides a recommendation of FACTS controller integration at inverter terminal having low ESCR.