Voltage profile improvement in the current northern power grid of Bangladesh: A techno-economic comparison of compensation strategies

The increasing integration of renewable energy into the Northern power grid of Bangladesh has exacerbated voltage stability challenges, driven by the widening gap between generation and demand. This study explores reactive power compensation strategies to enhance the voltage profile of the grid while ensuring economic feasibility. Initially, it explores the optimal placement of traditional reactive power compensation devices like capacitor banks, static VAR compensators, and synchronous condensers. Leveraging optimization algorithms like Genetic Algorithm and Particle Swarm Optimization, the study determined the most effective configurations for these devices. A pioneering aspect of this work involves the novel concept of repurposing retired power plants (independent power producers and quick rental plants) to function as synchronous condensers, tapping into existing infrastructure for a sustainable solution. Furthermore, a hybrid model combining capacitor banks with these repurposed plants is proposed and rigorously tested. A detailed grid model, developed using DIgSILENT PowerFactory 2021 with real-time generation and load data, facilitated comprehensive load flow and multi-year cost analyses across nine distinct simulation cases. The findings suggest that capacitor banks stand out as the most cost-effective individual option, but they lack dynamic reactive power support. Considering this trade-off, the hybrid model incorporating repurposed plants alongside capacitor banks offers the best balance between voltage profile improvement and cost-efficiency. Despite certain limitations, such as data availability and minor assumptions, this study offers practical and scalable strategies to address undervoltage issues in the evolving energy landscape of northern Bangladesh, paving the way for a more reliable and sustainable power grid infrastructure. • Real-time data to model renewable-integrated northern Bangladesh grid via DIgSILENT. • Dual-objective index for voltage stability enhancement and system cost minimization. • GA vs. PSO for optimal performance of reactive power compensation strategies. • Novel approach to repurpose retired plants, leveraging the existing infrastructure. • Hybrid model (retired plants + capacitor banks) optimizes cost-voltage balance.