High solar photovoltaic (PV) penetration in the electrical grid can result in undesired effects on the voltage quality, leading to line loss and voltage magnitude increases. One of the main criteria to ensure the safe penetration of high-power solar systems in the main grid is maintaining an acceptable voltage magnitude when a disturbance occurs (e.g., 0.95 and 1.05 per unit) with respect to total installed power generation capacity of PV power plants. This manuscript analyzes the effects of high solar PV penetration per unit of voltage stability using the Fast Voltage Stability Index and total power loss. Moreover, we investigate the flexibility benefits of coordinated voltage control based on a smart inverter of solar PV capacitor banks (SI-CBs) under five cases in a typical microgrid (MG) test model. For the test of the SI-CBs, MG modeling is developed on a modified IEEE 123 test feeder, which includes 11 building load solar PVs with smart inverters and capacitor banks with real-time data from an area in Los Angeles, California, USA. The simulation results are presented to validate the effectiveness of the proposed approach using a real-time MATLAB interface to the Open Distribution System Simulator (OpenDSS).

The United States is experiencing a large growth in the solar sector. The U.S. solar power capacity has grown from 0.34 Gigawatts (GW) in 2008 to an estimated 97.2 GW today. However, some states have had difficulty installing large scale solar farms due to concerns regarding geographic location, political climate, or economic factors. Kentucky (KY) is one of the states which is below the national average for solar energy production. However, KY contains a wealth of potential for these types of farms with decent solar irradiation levels and large tracts of unused land for solar farms. For the study, this paper selects three representative areas of KY by using PVWatts and topographical maps which can theoretically produce enough electricity so that KY can meet or exceed the national generation percentage average (2.3% or 2.06 TWh annually in KY’s case). The study analyzes the economic feasibility of solar photovoltaic systems (PV) farms in terms of Cumulative Cash Flow ($) and Payback Time (Year) by using the Cost of Renewable Energy Spreadsheet Tool (CREST). Furthermore, this paper estimates the Average/Median/High output power (kWh) annually for the scenario among three areas in Kentucky, Smithland, Hickman, and Falls of Rough. In this theoretical scenario, an average 2.27 TWh would be generated annually which exceeds the national generation percentage average. Furthermore, by the sixth year, the cumulative cash flow would exceed the breakeven point, proving the feasibility of these solar farms. The annual average power generation estimates for the areas of Smithland, Hickman, and Falls of Rough are 0.3741 TWh, 1.1628 TWh, and 0.731 TWh respectively. The average profit per MWh estimates for the areas of Smithland, Hickman, and Falls of Rough are $11,130.12/MWh, $10,742.46/MWh, and $11,392.01/MWh respectively. According to CREST, the final cumulative cash flow, after the 25-year life span of the panels, would be approximately $624,566,720.