Power control and instability mitigation in Kigali National Grid

Abstract

The transmission grid is the backbone of the power system, and its stability and reliability are essential for the proper functioning of the entire electrical grid. The increased demand for electricity, coupled with the integration of renewable energy sources, has led to the reinforcement of the transmission grid. The newly reinforced transmission grid is characterized by longer transmission lines, higher capacities, and a more complex network, which pose new challenges to the protection coordination system. In particular, communication delays and cyber-attacks are becoming increasingly relevant issues that must be taken into account when designing the protection coordination system. The problem of communication delays and cyber-attacks persists in the recently strengthened transmission system. The grid's strength lies in its ability to impact the protection coordination system's ability to operate correctly. Cyber-attacks may disrupt the protection coordination system by compromising its communication network or by disrupting the operation of protective devices. The impact of communication delays and cyber-attacks on protection coordination in the newly reinforced transmission grid is a critical issue that requires immediate attention. The consequences of incorrect protection coordination can be severe, including the failure of transmission equipment, blackouts, and even the collapse of the entire electrical grid. To prevent these events, it is essential to understand the impact of communication delays and cyber-attacks on protection coordination and to develop new methods to mitigate their effects. The IEEJ West 10-machine model system, IEEE 14-bus system, and Kigali national grid that serves the city of Kigali in Rwanda are widely used in power systems research. In this research, we aim to use these systems to address several objectives: For the first objective, it aims to develop new techniques and algorithms to reduce the communication delay of electric power, which impacts control system performance and also can create energy losses. This study also examined the implications and causes of network latency while maintaining model reliability simulation using the IEEJ West 10-machine electric grid. For the second objective, which aims to develop new techniques and algorithms to reduce the impact of the delay time for underfrequency load-shedding on protection coordination in the comparison of algorithms, in this study it is focused on a test case used to evaluate the performance of different energy control strategies and to develop new methods to improve the protection of IEEE 14 bus system. The third objective aims to develop new techniques to negatively impact decision interaction on grid access control. This case study concentrates on communication signal latencies as well as how to detect them but also addresses communications network performance concerns inside the context of energy control and surveillance, including a particular on characteristics of the technology delays. An implementation to resolve this difficulty using SVC (TSC-TCR) thyristor switch capacitors (TSC) and thyristor-controlled reactors (TCR) to enhance the xii system reliability of the Kigali national grid. Finally, the last objective aims to formulate methods that utilize smart systems, the much more prevalent type of cyber-physical network that provides a strong association between cyber communications and physical networks. For that reason, it is really critical to investigate how cyber-attacks affect frequency relay equipment and a circuit breaker as a control system of the automatic generator, located in the Kigali national grid. The impact of cyber-attacks that cause information network latency and their effects on transient stability are covered in this research. Utilizing measurement result devices, such as an SVC or STATCOM connected to such a grid, cyber-attacks have been conducted. These case studies can be used to address various interventions related to the analysis and evaluation of various control techniques for improving power quality in the transmission grid system. In the first case, the IEEJ West 10-machine model system can be used to evaluate the performance of different power system stabilizers. In the second case, the IEEE 14 bus system can be used to test the performance of different control strategies. In the third case, the Kigali national grid can be used as a case study to address challenges such as grid integration of renewable energy sources, demand-side management, and grid reliability. For instance, the study of the use of non-linear control strategies to reduce the negative consequences of significant delays in electricity performance improvement. In the final case study, KNG focused on addressing the challenges of detecting and reducing these effects based on the different cases of limited-frequency relay devices. In summary, the use of these case studies can provide valuable insights into the challenges and opportunities associated with power system operations and management. They can help identify the most effective solutions to these challenges and develop new methods and strategies for enhancing stability, reliability, and sustainability of power systems. The results showed that the suggested approaches outperformed the conventional approach, providing a solution to the challenges faced in the IEEJ West 10-machine model system. The simulation results confirmed the effectiveness of the grasshopper optimization algorithm (GOA) and particle swarm optimization (PSO) methods for reducing the negative consequences of under-frequency load-shedding (UFLS) in the IEEE 14-bus system. Moreover, the results indicated that non-linear control strategies, such as fuzzy logic control (FLC) and other modified predictor (MD) controlled SVC effectively reduced the negative consequences of significant delays in electricity performance improvement. SVC and STATCOM simulations also showed promising results that the two new methods for reducing the adverse effects of cyber-attacks on a frequency relay and circuit breaker control system for the nonlinear (NL) controller and the proportional-integral (PI) controller were effective in reducing the consequences of cyber-attacks in the KNG. In conclusion, the MATLAB/Simulink simulation results confirm the effectiveness of proposed new control xiii methods and their superiority over traditional approaches for contributing to power quality improvements and suggest potential for further research in the field.