Index Based Techno-Economic Assessment of FACTS Devices Installed With Wind Farms

With the rising demand for electricity and limited fossil fuel reserves, wind energy conversion systems are nowadays considered a pivotal and indispensable resource within the realm of alternative power generation. Flexible AC Transmission Systems (FACTS) devices can be utilized to improve the voltage profile and stability in the presence of large wind farms. This study presents a comprehensive techno-economic assessment for different FACTS devices used with wind farms. In the technical assessment, the improved voltage (IV) index is presented to quantify the contribution of the Static Synchronous Compensator (STATCOM) and Unified Power Flow Controller (UPFC) devices with the focus on the improvement of the voltage levels during different types of faults. In the economic assessment, a cost comparison between the chosen FACTS devices is presented, where a cost related (CR) index is proposed which considers the investment cost in the FACTS device and the minimum revenue that could be obtained as a result of FACTS installation to keep the wind farm connected as a result of the voltage improvement during faults. In addition, guidelines to calculate the threshold for annual additional energy from the wind farm and its revenue needed to compensate for the FACTS device total cost are presented. To consider the environmental impact, the role of the FACTS devices on reducing CO2 emissions, and the associated carbon credit certificates, is considered. Finally, to combine both assessments, a new weighted techno-economic (TEI) index is presented which combines the IV and the CR indices obtained from the technical and economic assessments, respectively. This index will assist system operators in selecting the optimal device, where a breakeven point serving as the criterion for selecting the best device based on the proposed approach. The results show that the TEI index for the proposed system indicates that the STATCOM is considered a preferable solution when the focus is towards the economic weight. On the other hand, the UPFC becomes a preferable solution when the technical aspect is more important to the system operator. In this study, a technical weight of 0.8364 (economic weight of 0.1636) is the turning point between the two devices. Below this weight, the STATCOM is more suitable for installation and above this weight, the UPFC is a preferred option.