Research Projects

Indian power system is going through a radical change with growing penetration of renewable energy sources (RESs) into the grid and moving towards the ambitious target of meeting 50% of total energy demand with renewable energy sources by 2030, as set in COP 26 summit in 2021. In addition to the variability and intermittency issues with renewable energy sources, numerous control options embedded in the interfacing converters are resulting in an unprecedented change in the grid dynamics including system inertia and fault characteristics compared to the situation with only conventional synchronous machine based generating units. Thus, the power grid is becoming more volatile and uncertain, and affecting the transient stability and protection of the system. Three factors are identified influencing transient stability of the system and relay malfunctions which are (i) reduced and dynamic system inertia, (ii) modulation of voltage and current waveforms, and (iii) system non-homogeneity due to source impedance modulation by the converter control operation. Reduced and dynamic system inertia leads to instability of the system even following a non-severe disturbance and also challenges the threshold setting for conventional power swing blocking functions associated with distance relays and leads to relay malfunction. Modulation of current waveforms inhibit the extraction of fundamental current components during the transient period following fault inception which is a fundamental requirement for correct operation of any protection functions. System non-homogeneity limits the performance of local data-based protection schemes, sometimes the performance of current differential scheme too. Wide deployment of phasor measurement units (PMUs) in Indian power grid is providing a scope to access the high-resolution synchronized data throughout the system. Noticeable advancement in the application of Artificial Intelligence (AI)/ Machine Learning (ML) techniques may be helpful in deriving improved situational awareness and proper corrective actions during transient conditions with the available high-resolution synchronized PMU data. Concept of Digital Twin (DT) provide a safe, repeatable and controlled testing environment, where new solutions can be tuned and validated through multiple tests and conditions. Thus, the challenges associated with transient stability and protection in the system introduced by the growing penetration of different RESs can be handled efficiently. In this respect, a proposal is provided here about developing a hybrid AI-assisted digital twin framework for transient stability assessment and correct relay setting for the power system in the presence of different renewable sources with varying penetration levels.