Design and floating solar photovoltaic system intergrated with a hydropower plant (A case study Nyabarongo HPP dam)

Abstract

Renewable energy, particularly solar photovoltaic, offers great solutions to the current energy crisis that people face in their daily lives due to its cleanliness, advantages, and low cost of technology. The dissertation intends to demonstrate to the public, policymakers, and policy executors that sufficient exploitation of available water resources and solar energy abundant in the country can ensure the sustainability of electric energy as well as renewable energy development in Rwanda. The dissertation's main goal is to design a floating solar photovoltaic system integrated with a hydropower plant (a case study of the NYABARONGO Dam). The potential energy of floating solar photovoltaic (FSPV) on the Nyabarongo hydro power plant (HPP) dam is modeled and simulated using PVsyst software, and Matlab was used to validate the thesis results and analyze the impact of floating solar photovoltaic (FSPV) integrated with hydropower plant on the national grid. The control system includes a maximum power point tracker, which locates the point at which the photovoltaic modules produce the most power under varying operating conditions. The phase locked loop (PLL) is used to quickly synchronize the PV system with the grid by locking the converter output to the grid voltage. The rotating reference frame locked to the grid is used to control current and voltage towards active and reactive power flow. Furthermore, the study demonstrates the benefits and potential of using floating solar photovoltaic (FSPV) in Rwanda to reduce the use of land-mounted solar photovoltaic (SPV), as floating solar photovoltaic (FSPV) is found to be more efficient than traditional SPV due to its cooling facilities. A total of 33,750 photovoltaic modules were used on a small surface area of 72,884 m2 extracted from a large surface area of the Nyabarongo hydro power plant (HPP) dam, injecting 15 MWp into the grid at a nominal power ratio of 1. Five 3,000 kW inverters, each operating at 630-930 VDC and 400 VAC at its output, were used to connect the FSPV to the grid, and MATLAB software (Version 2017) was used to simulate its performance with an inductor-capacitor-inductor (LCL) filter. The proposed model includes PV arrays, a closed loop boost converter to control the effects of weather on the floating solar photovoltaic (FSPV), and an inverter with an LCL filter to suppress harmonics in the system. The system parameters were tuned so that the total harmonics distortion of current and voltage respects the IEEE (519-2014) standards. It is ensured that the production of Nyabarongo hydro power plant (HPP) has been improved because with FSPV inject 28 MW or more into the grid at all times. The results show that the floating solar photovoltaic (FSPV) makes the best use of existing infrastructure and could supplement existing hydroelectric production as well as provide electricity in conjunction with hydro power plant's existing generating units.