On standards for interconnecting distributed resources

This paper addresses the application of standards for interconnecting distributed resources (DR) to distribution systems. DR interconnection requirements have evolved over 25 years and are sometimes seem as confusing, even conflicting, particularly for inverter-based technologies such as solar photovoltaics (PV). Today there are several current standards, e.g., IEEE Std 1547/spl trade/-2003, UL 1741, and IEEE Std 929-2000. Industry efforts to reconcile these are discussed. Also considered are various state interconnection regulations, such as California rule 21, and net metering rules that apply to renewable DR. The recent movement to establish state renewable portfolio standards (RPS) is expected to significantly increase the number and size of DR installations such as wind and PV. This paper should be useful for distribution engineers to better understand how to deal with requests for interconnections and the application of relevant standards and regulations. Relevant study procedures for analyzing impacts of interconnecting DR are also described. Examples of PV interconnections are given.