Sarasij Das
Research Highlights
Application of Smart Meters in Protection of Distribution Systems
Penetration of Distributed Generations has made traditional distribution protection schemes mostly ineffective. Sophisticated protection schemes cannot be implemented using fuses, reclosers and Miniature Circuit Breakers (MCBs). Economics often limits the use of sophisticated relays in distribution systems. Smart Meters (SMs) are available at various load points in a distribution system. SMs are equipped with measuring, calculation and communication capabilities. We are working towards implementing protection functionalities in SMs. The possible applications of SMs in high impedance fault (HIF) detection, overcurrent, reverse power, series arcing and under-voltage protection of distribution systems are identified. One of the advantages of the proposed approach is that voltage-based protection can also be implemented using SMs. As a part of hardware validation, protection functionalities have been implemented in a commercial SM. The commercial SM is modified to trip a Moulded Case Circuit Breaker (MCCB) upon detecting a fault.
Addressing Stability Issues of Renewable Energy Dominated Power Systems
In future, power grids are expected to operate with large scale penetration of Renewable Energy (RE) sources. Conventional Synchronous Generators are getting replaced by Converter Control Based Generators (CCBGs). The power electronic interface used for Renewable Energy generations results in decrease of overall rotational inertia in a power system. The intermittent nature of Renewable Energy sources poses a threat to power system stability. In addition, control loops of CCBGs and their interaction introduces new problems related to stability of power system. We aim at understanding the stability issues arising due to large scale renewable penetration and developing new controllers to address the identified stability issues. Energy storage stabilizer based on robust control theory has been proposed to improve the small signal stability of Renewable Energy dominated power system. Impact of Phase Locked Loop (PLL) on interactions among electromechanical oscillations and oscillations due to control loops has been identified. Tuning of PLL parameters is proposed to avoid poor damping of system oscillations due to these interactions. We are currently analysing the impact of PLL on harmonic stability of Renewable Energy dominated power systems.