The protection issues surrounding multiterminal High Voltage Direct Cur- rent (MT-HVDC) grids based on Voltage Source Converters (VSC) are ex- amined in this thesis, with an emphasis on the function of hybrid HVDC circuit breakers in reducing DC-side faults. The study emphasises how im- portant it is to isolate and detect faults quickly, accurately, and specifically as HVDC networks become more intricate as a result of the growing inte- gration of renewable energy sources. The study evaluates the performance of hybrid HVDC circuit breakers under various fault scenarios by compre- hensive modelling and simulation using Simulink, demonstrating their ef- ficiency in shortening fault clearing times and improving system stability. Undervoltage, overcurrent, and current/voltage derivative-based fault de- tection algorithms are compared, and the results show that voltage-based techniques perform better in high-resistance fault scenarios.Hybrid HVDC circuit breakers, which combine the reliability of mechanical disconnectors with the speed of solid-state devices, are identified as a promising solu- tion for modern MT-HVDC grids. This research contributes valuable insights into the design and application of hybrid HVDC circuit breakers and protection algorithms, showing that they significantly improve the operational safety and reliability of HVDC grids. Future studies ought to concentrate on lowering power losses that occur during regular operations and improving the scalability of hybrid HVDC circuit breaker designs for bigger grids. It is projected that improvements in self-triggering mechanisms and circuit breaker technology will further reduce conduction losses and speed up operation. Furthermore, the inte- gration of machine learning (ML) and artificial intelligence (AI) into fault detection algorithms presents a promising opportunity to enhance detec- tion efficiency and precision, all the while accommodating dynamic grid conditions. The effect of communication latency on problem detection may be lessened by investigating communication-independent protection systems, such as travelling wave-based methods. For a viable deployment, extensive testing and validation in real HVDC grid environments are nec- essary, and complicated failure scenarios should be simulated in order to better inform future implementations.By addressing these issues, HVDC grid protection will be improved, along with system efficiency, depend- ability, and capacity to handle the increasing needs of renewable energy integration
