IEEE 1547 (Standard for Interconnecting Distributed Resources with Electric Power Systems) is a standard of the Institute of Electrical and Electronics Engineers meant to provide a set of criteria and requirements for the interconnection of distributed generation resources into the power grid in the United States.
"This document provides a uniform standard for interconnection of distributed resources with EPSs [Electric Power Systems]. It provides requirements relevant to the performance, operation, testing, safety, and maintenance of the interconnection."
With the increased adoption of distributed resources in the present and future, a set of standards regarding their usage in the grid becomes increasingly important for the overall reliability, safety, and cost. Furthermore, the lack of a concrete national standard was seen as a roadblock to the implementation of new distributed generation projects. The standard is intended to be universally adoptable, technology-neutral, and cover distributed resources as large 10 MVA.
In early 1999, the IEEE approved the undertaking of P1547. With the support of the United States Department of Energy, the project was initiated on a fast-track basis, which would halve the usual development time. The draft standard was revised 10 times before P1547/Draft 11 was approved with a 91% vote in February 2003. It was then approved by the IEEE Standards Board on June 12, 2003, and received an ANSI designation on October 20, 2003.
Risk of System Disturbance 
IEEE 1547-2003 has a tight underfrequency protection setting of 59.3 Hz which poses a risk for grid stability. In case of an underfrequency situation, e.g. after a major loss of generation, the situation may get worse when a multitude of distributed energy resources (DER) disconnect simultaneously. IEEE 1547-2003 demands also an obligatory overfrequency disconnection at 60.5 Hz. With a rising share of distributed generation there is a possibility of triggering a non-linear oscillator in the multi GW range within the transmission grid. In Europe, this problem with similar standards has already been addressed by ENTSO-E.
Energy Policy Act of 2005 
“Interconnection services shall be offered based upon the standards developed by the Institute of Electrical and Electronics Engineers: IEEE Standard 1547 for Interconnecting Distributed Resources With Electric Power Systems, as they may be amended from time to time.”
Related Standards 
Currently, there are six complementary standards designed to expand upon or clarify the initial standard, two of which are published, and the other four still in the draft phase.
- IEEE 1547.1, published in 2005, further describes the testing of the interconnection in order to determine whether or not it conforms to standards.
- IEEE 1547.2, provides a technical background on the standard.
- IEEE 1547.3, published in 2007, details techniques for monitoring of distributed systems.
- IEEE 1547.4, is a guide for the design, operation, and integration of conforming systems.
- IEEE 1547.5, is designed for distributed sources larger than 10 MVA
- IEEE 1547.6, describes practices for secondary network interconnections.
- http://grouper.ieee.org/groups/scc21/1547/1547_index.html (IEEE 1547 Homepage)
- Vaughn (2007-12-21). "IEEE SCC21 1547 Home Page". IEEE. Retrieved 2008-01-26.
- Thomas Basso and N. Richard Friedman (November 2003). "IEEE 1547 National Standard for Interconnecting Distributed Generation: How Could It Help My Facility?". Distributed Energy. Retrieved 2011-08-28.
- E. Grebe, D. Klaar et al. (April 2004). "Final Report of the Investigation Committee on the 28 September 2003 Blackout in Italy". Brussels: UCTE. Retrieved 2011-08-28. Please compare with Chapter 6.3.5 and 6.4.1: "For instance, due to its significant penetration level, the effect of the distributed generation may no longer be neglected and appropriate technical requirements need to be defined." p. 94
- Letter, 18 July 2011 from Mr. Dobbeni, President of ENTSO-E to Mr Oettinger, European Commissioner for Energy
- "Energy Policy Act of 2005 SEC 1254" (PDF). August 5, 2005. Archived from the original on 2007-12-01. Retrieved 2008-01-26.