NIST Smart Grid and Cyber-Physical Systems Newsletter - June 2020

• NIST Helps Develop IEEE Standards for Distributed Energy Resources on the Grid
• NIST and University of Vermont Researchers Develop "Overshoot" Mitigation for Grid
• NARUC Issues Smart Grid Interoperability Guide, Videos for Regulators, Aided by NIST
• NIST-led Technical Working Group Advances Automated Driving System Safety Concepts
• In the News: Signal Reports GCTC ActionCluster Developing Secure Cloud architecture

NIST Helps Develop IEEE Standards for Distributed Energy Resources on the Grid

With the increasing use of distributed energy resources (DER) – solar, wind, electrical storage and more – the IEEE established the 1547-2018 standard to ensure that they would operate properly on the grid, without causing adverse effects. This standard specified functionality, performance measures, and capabilities for DER when connected to the grid. A continuing challenge has been to ensure that various DER available in the marketplace conform to the standard.

An IEEE working group, aided by NIST’s Cuong Nguyen, pursued verification of DER conformance with the standard. The effort resulted in IEEE 1547.1-2020, published May 21, 2020, which provides a testing methodology, procedures, test cases and scenarios for verifying DER conformance with 1547-2018. Nguyen also participated in a working group that amended the base standard, IEEE 1547a-2020, as published on April 15, 2020. The amendment defines the functionality needed for DER to operate in abnormal conditions and standard operating conditions, improving their flexibility on the grid. Collectively, these standards enabled the interconnection and interoperability of distributed energy resources (DER) with the electrical grid.

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NIST and University of Vermont Researchers Develop "Overshoot" Mitigation for Grid

The electrical distribution system is evolving, with multiple intelligent agents producing power. It requires the ability to coordinate and optimize these multiple agents, so as to balance changing demands, or improve the quality of power. Additionally, the electrical distribution system must continuously update the amount of power each agent produces to meet grid constraints.

At times, distributed energy resources (DERs) – solar, wind, electrical storage and more -- may temporarily supply more power than is needed, or "overshoot," as they are attempting to track set points. With a large enough number of DERs in a circuit, even a small overshoot, in aggregate, can overload sensitive electronic power converters, affect power quality, and make the grid less stable. Mitigating overshoot using conventional methods can be difficult, given the diversity in DER morphology and tracking response.

NIST's Dhananjay Anand and University of Vermont's Colin Freiheit and Hamid Ossareh developed a new approach to mitigate overshoots by designing a dynamic constraint management system called the "Reference Governor with Dynamic Constraints." This work extends prior developments in the field of set-theoretic reference governors by accommodating time-varying or dynamic grid constraints. Unlike existing methods, the proposed strategy does not require modification of existing closed-loop controllers, does not require model inversion, and can be made robust to modeling errors.

The Reference Governor represents a first step towards implementing operational strategies to improve grid stability, while maximizing DER throughout the system. The approach was reported in Overshoot Mitigation Using the Reference Governor Framework, published in IEEE Control Systems Letters, January 13, 2020.

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NARUC Issues Smart Grid Interoperability Guide, Videos for Regulators, Aided by NIST

For over a decade, NIST has advocated for and provided a foundation for smart grid interoperability. In April 2020, the National Association of Regulatory Utility Commissioners (NARUC) advanced it further, publishing Smart Grid Interoperability: Prompts for State Regulators to Engage Utilities, along with Interoperability Learning Modules. The effort was aided by NIST's Avi Gopstein, Cuong Nguyen and David Wollman.

The Prompts for State Regulators provides questions for regulators and others to consider when reviewing utility proposals for new technologies. Questions are posed in the following steps, enabling regulators to investigate interoperability issues, many of which are described and addressed in NIST smart grid frameworks:

• Step 0 Questions: Enabling regulators to assess their own capabilities in guiding utilities’ initiatives
• Step 1 Questions: Helping understand a utility's business case for interoperability investment
• Step 2 Questions: Determining if new equipment will work with legacy equipment
• Step 3 Questions: Assessing whether today's investments will support tomorrow's investments
• Step 4 Questions: Determining need for an interoperability profile and what it may include

NARUC-produced Learning Modules, a series of short videos, augment this guidance. These videos provide additional information and context to support state utility commissions, including those on the economics of interoperability, its operational considerations, and the roles and responsibilities of state regulators, with additional videos to be added over time.

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NIST-led Technical Working Group Advances Automated Driving System Safety Concepts

In April, NIST began online meetings of its Automated Driving Systems Operational Design Domain Technical Working Group (ADS-ODD TWG) to develop consensus-based measurement methods for Automated Driving System (ADS) safety. The meetings have included participation by approximately 35 stakeholders, who are contributing and evaluating concepts for ADS safety measurement, drawing from their experience at automotive-related companies and organizations, including manufacturers/suppliers, standards and testing, academia and government.

The working group is evaluating the situations that automated vehicles will encounter – or "Operational Design Domain" – and exploring the concept of an Operational Envelope Specification as the basis for measurement methodology to assess ADS safety performance. The technical working group follows the findings of a 2019 NIST's Workshop Report: Consensus Safety Measurement Methodologies for Automated Driving System (ADS) Equipped Vehicles, which recommended that the Operational Design Domain be the focus of further work on measuring ADS safety.

The technical working group will present its initial findings for broad stakeholder review at a virtual workshop, July 7-8, 2020. Breakout groups will consider the Operational Design Domain and Operational Envelope Specification, as viewed through the lens of the NIST's Cyber-Physical System framework. When completed, the working group’s technical findings will be made public. The ADS-ODD TWG is open to participation; if interested, contact NIST’s Ed Griffor at email edward.griffor [at] nist.gov (edward[dot]griffor[at]nist[dot]gov).

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In the News: Signal Reports GCTC ActionCluster Developing Secure Cloud architecture

Signal, a defense trade publication, detailed NIST's Global City Teams Challenge (GCTC) and one of its ActionCluster's efforts to develop a secure cloud architecture, in Cloud Architecture Offers Security to Cities, May 1, 2020. The article reported that SC3 cloud privacy, Security, and Rights-Inclusive Architecture (cpSRIA) ActionCluster had been working on the architecture over the last year and half.

The article also stated that the architecture could help local governments guard against cyber attacks, protect citizens’ information, and safely rely on Internet of Things in doing daily governmental business. The architecture uses color-coding to show data risks: red equals sensitive information; yellow indicates privacy rights; and green implies publicly available data. Presently, the ActionCluster is advising the city of Syracuse on the architecture's application for smart streetlights, water metering, catch basins, and facial recognition. The city is evaluating the architecture and how best to use the data.

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