Integrated high-speed intelligent utility tie unit for disbursed/renewable generation facilities

Following the steps of the gas industry, the traditional paradigm of the vertically integrated electrical utility structure has begun to change. In the United States, the Federal Energy Regulatory Commission has issued several rules and Notices of Proposed Rulemaking to set the road map for the utility deregulation. The crisis in California has drawn great attention and sparked intense discussion within the utility industry. One general conclusion is to rejuvenate the idea of integrated resource planning and promote the distributed generation via traditional or renewable generation facilities for the deregulated utility systems. Fuel cell and photovoltaic are the most promising renewable generation technologies for the residential and small commercial users. 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 makes 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 paper discusses the development of an integrated high-speed intelligent utility tie monitoring, control, and protection system to replace the traditional tie breakers for those residential and small commercial facilities with disbursed/renewable generation facilities.