Planning, optimization and efficiency improvement of telecommunications solar plants
Loading...
Date
2023
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
National University of Lesotho
Abstract
Mobile network operators (MNOs) in Lesotho have recently experienced an increase in deploying solar PV-powered base stations in off-grid and bad-grid areas to improve their network coverage to the most underprivileged communities. This justifies the need to model and design the optimal solar PV- battery systems to power telecom base stations (BSs) operating in high-speed technologies that meet both the MNO and regulator targets and act as enablers for other economic sectors in rural areas. This research primarily aimed to audit the existing Vodacom Lesotho solar PV-powered BSs through physical inspections, configurations assessment, and load profile analysis using historical data. Based on the audit results, retrofitting and parameter optimizations were implemented to improve major key performance indicators (KPIs), therefore maximizing telecom solar power plants' energy yield and solar PV arrays' performance ratios (PRs) in a cost-effective and environmentally friendly manner. Five solar PV-battery-powered BSs with different power and radio configurations were selected, and their KPIs, such as battery charging current, solar PV generator power, load current, and PR, were assessed, analysed and optimized for possible maximum energy yield.
The Makebe BS improved charging currents by 15% with no improvements in other KPIs. The Malimong BS increased charging current by 23%, current from the solar generator by 12%, power by 11%, and PR by 3.31%. Mmasemouse BS showed an improvement of 34% in charging current, 19% in harvested current, 17% from the generated power after rewiring and optimizations, and 7.31% in PR. After replacing the faulty batteries and conducting a parameter optimization at Ha Tlhoro, the Tlhoro BS solar plant increased charging current by 60%, harvested current from the solar PV generator by 90%, generated power by 46%, and PR by 20%. After integrating two standalone solar arrays into one, rewiring, increasing the charging current limit and replacing faulty batteries for a high-capacity solar-powered BS in Kolo, it improved solar PV generator current by 7%, battery charging current by 19%, solar PV power by 40%, PR by 19% and able to reach 100% state of charge (SoC).
One high-capacity and grid-powered BS in an urban area was assessed and dimensioned for grid-to-solar migration with a 20.8 kWp solar PV array, 27 kW solar PV charge controller, and 1200Ah backup batteries storage for 0.5 days of autonomy using the month of June, which has the lowest peak sunshine hours (PSH) as the design month for maximum system reliability.