Re-use of existing system protection concerns and interconnection rules for integration of future Distributed Generation

Interconnection of Distributed Generation (DG) to the distribution system results in some significant system protection related impacts. Existing interconnection rules and standards such as the State of California Public Utilities Commission (CPUC) Rule 21 address some of the existing concerns. This paper attempts to highlight information about major protection related concerns and associated Rule 21 criteria. The information may be re-used for the future integration of DG. Implementation problems and issues associated with the presently used methods and rules will be discussed. Known problems due to relay desensitization will be simulated using industry level software and analysis will be produced. The paper summarizes problems and issues with the interconnection of increasing levels of DG.