Distributed resources (DR), such as residential small wind turbines and solar cells, generate electrical energy in the form of a direct current (DC). An inverter is needed to convert this DC power into an alternating current (AC) for regular usage. The main purpose of this dissertation was to determine the performance of the inverter under steady-state and transient-state conditions, and then develop a power flow model that would be useful for power system operators and planners to determine how much high penetration of distributed photovoltaic energy would affect their power systems. These test results are useful for analyzing the inverter behavior in order for power system operators and planners to regulate the active power and reactive power flow if 5% to 10% of renewable energy penetrates into their neighborhoods in the near future.