NIST SP 1108r4: NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 4.0

Overview

The framework defines interoperability as the ability to exchange information in a timely, actionable manner and calls it a critical yet underdeveloped capability of the power system: despite grid modernisation in recent years, the proliferation of technology and standards has only modestly improved it. Distributed and customer-sited resources and intelligent distribution systems figure prominently in the future smart grid. Interoperability hedges against obsolescence, raises the value of equipment investments through secondary uses, and enables combinatorial innovation by letting coordinated small actions by diverse stakeholders have large effects.

Section 2 updates the models: the NIST Smart Grid Conceptual Model (customer, markets, service provider, operations, generation including DER, transmission and distribution domains), legacy, high-DER, hybrid and microgrid communication pathways scenarios, and a smart grid ontology built on the cyber-physical systems framework. Section 3 covers operations: interoperability for utilities and new technology, evolving control schemes, and requirements for metrology, observability and controllability. It stresses that the move from analogue to digital energy technologies changes physical dynamics at the system edge, so physical interoperability must complement informational interoperability.

Section 4 covers economics: traditional ratemaking and cost recovery are strained by DER growth, and interoperability reduces information asymmetry, transaction costs and entry barriers and lessens the limits of asset specificity. Section 5 addresses cybersecurity: practice must evolve beyond physical isolation and overly restrictive access, and the document offers the Cybersecurity Framework functions and a Cybersecurity Risk Profile for the smart grid (Appendix G); new interfaces can be mapped to existing logical interface categories and protected with known standards.

Section 6 covers testing and certification. Smart grid standards contain many user-selected options that allow non-interoperability even among products conforming to the same standard, so certifying conformance to individual standards is inadequate. The proposed solution is Interoperability Profiles: subsets of requirements drawn from existing standards, not new standards, that ensure interoperability when implemented and verified through testing and certification. Appendices include the conceptual model domains, inverter and DER functions, electric industry roles, and distribution platforms and markets.

Key points

1. Interoperability is the ability to exchange information in a timely, actionable manner; proliferating standards have only modestly improved it.
2. It hedges against technology obsolescence, raises equipment investment value and enables combinatorial innovation.
3. The conceptual model has seven domains: customer, markets, service provider, operations, generation including DER, transmission and distribution.
4. Four communication pathways scenarios are presented: legacy, high-DER, hybrid and microgrid.
5. The analogue-to-digital transition changes physical dynamics at the system edge; physical interoperability must complement informational interoperability.
6. Interoperability reduces information asymmetry and transaction costs and lowers market entry barriers.
7. Cybersecurity must evolve beyond physical isolation; new interfaces can be mapped to existing logical interface categories.
8. The Cybersecurity Risk Profile for the smart grid (Appendix G) assesses organisational readiness in a structured way.
9. Certifying conformance to individual standards is insufficient because user-selected options allow non-interoperability.
10. Interoperability Profiles are subsets of requirements from existing standards, not new standards.

Using it in design

• Decide which communication pathways scenario (high-DER, microgrid) applies to on-site generation, batteries and flexible load in the facility's electrical infrastructure.
• Clarify metering, observability and controllability requirements (metrology, data rates) with the utility at the start of design.
• When buying inverter and DER equipment, ask for an Interoperability Profile and test evidence, not only a standards conformance certificate.
• Assess risk for new grid and DER interfaces using existing logical interface categories and the cybersecurity profile.
• Prefer interfaces built on open standards as protection against technology obsolescence.

Who should read it

Engineers designing grid interfaces, DER and microgrids, utilities, standards developers and policy makers.

Document contents

1. Key Messages
2. 1. Purpose and Scope
3. 1.2 The Role of Interoperability
4. 1.3 Framework Content and Structure
5. 2. Models for the Smart Grid
6. 2.1 NIST Smart Grid Conceptual Model
7. 2.2 Communication Pathways Scenarios
8. 2.3 An Ontology for the Smart Grid
9. 3. Operations
10. 4. Economics
11. 5. Cybersecurity
12. 6. Testing and Certification
13. 6.5 Towards Interoperability Profiles
14. Conclusion
15. Appendix A. Smart Grid Conceptual Model Domains
16. Appendix B. Mapping CPS Aspects and Concerns to the Electrical Grid
17. Appendix C. Inverter and DER Functions
18. Appendix D. The Core Set of Electric Industry Roles
19. Appendix E. Cost Recovery, Rate Design, and Regulation
20. Appendix F. Distribution Platforms and Markets
21. Appendix G. Smart Grid Cybersecurity Profile Subcategory Prioritization and Considerations Matrices

Related standards

• IEEE 1547
• IEEE 2030.5
• NIST CSF

Read the document

Publication details

Authors

Avi Gopstein; Cuong Nguyen; Cheyney O'Fallon; Nelson Hastings; David Wollman

Publisher

National Institute of Standards and Technology

Year

2021

Document number

NIST SP 1108r4

Document language

English

Source type

Expert / community

Access

Open licence — downloadable

DOI

10.6028/NIST.SP.1108r4

Licence

U.S. public domain — U.S. Government work; free to reuse

Licence evidence

www.copyright.gov

Citation