What interconnection standard governs the integration of distributed energy resources, including ESS, into the grid in the United States?

The primary interconnection standard governing the integration of distributed energy resources (DERs), including Energy Storage Systems (ESS), into the electric grid in the United States is IEEE Standard 1547. IEEE 1547 establishes the criteria and requirements for the interconnection of DERs with electric power systems. These requirements cover a range of technical aspects to ensure the safety, reliability, and power quality of the grid. The standard addresses voltage regulation, requiring DERs to operate within specified voltage limits and contribute to voltage stability. It also sets forth requirements for frequency regulation, dictating how DERs must respond to changes in grid frequency to maintain system stability. Furthermore, IEEE 1547 outlines protection requirements to prevent DERs from causing or exacerbating faults on the grid. These protection schemes include over- and under-voltage protection, over- and under-frequency protection, and ground fault protection. The standard also includes anti-islanding requirements, which mandate that DERs must automatically disconnect from the grid if the grid loses power to prevent them from energizing a de-energized section of the grid, which could be hazardous to utility workers. IEEE 1547 also specifies testing and certification requirements to ensure that DERs meet the standard's technical criteria. The standard is periodically updated to address evolving grid conditions and technologies, and regional and local authorities may also have their own interconnection requirements that build upon or supplement IEEE 1547. Compliance with IEEE 1547 is essential for ensuring the safe and reliable integration of ESS and other DERs into the electrical grid in the United States.