Integrated High Speed Intelligent Utility Tie Unit For Disbursed/renewable Generation Facilities

After experiencing the price hikes and rotating blackouts in California, the disbursed or distributed generation (DG) is considered as one of the most attractive alternatives for future utility industry. In addition to the conventional DG that uses fossil-fuel to generate power, the DG via renewable energy is of interest due to the environmental concern. Fuel cell and photovoltaic are the most promising technologies for the urban residential and small commercial users. For economic and reliability purposes, it is desirable for these facilities to be interconnected with the utility grid to perform peak shaving, demand reduction, and to serve as emergency and standby power supply. However, the mismatch between the utility tie protection and the equipment protection make it impossible for the fuel cell and/or photovoltaic to serve as emergency and standby power supply when the utility supply is lost due to nearby external faults. To overcome this issue, this dissertation proposes the development of an integrated high-speed intelligent utility tie unit (IUT) to monitor, control, and protect the system for residential users to enable their disbursed/renewable generation facilities to serve as emergency and standby power supply. The proposed algorithm of the IUT is verified with computer simulation and experimental results.