Research Highlight

Advancing grid resiliency, security with a microgrid test bed: SI-GRID

L-R: Ben Ollis, Ishita Ray, and Phil Irminger in a Power and Energy Systems group lab with SI-GRID components.

A unique, low-voltage test bed established at Oak Ridge National Laboratory (ORNL) is providing researchers a safe way to evaluate the operation and cybersecurity of equipment developed to support a growing number of microgrids—or local electric grids formed when residential or business customers install distributed energy resources (DER) like solar panels and batteries.

These microgrids, made up of any combination of generation and storage resources sited away from central power plants—such as wind turbines, small generators, onsite energy storage, and even electric vehicles—can disconnect from the larger utility system and reconnect as needed. But these variable DERs require controllers and must be protected against cyberintrusion.

Software-Defined Intelligent Grid Research Integration and Development, or SI-GRID, is an ORNL-developed open research platform to safely test microgrid components in low-voltage settings that mimic real-world, high-voltage applications. The platform is being used to develop and rapidly prototype technologies associated with microgrids, including power electronics–based converters, generation technologies, energy storage, protection, cybersecurity methods, communications protocols, control, optimization, standardization, and integration of DERs, buildings, and vehicles.

The SI-GRID test bed prototype. (hi-res image)
All system components operate below 100 volts but mimic the physics of larger, higher-voltage operations. The system is safer and cheaper to operate than a full-scale platform; if a part is damaged during testing, it can be replaced at much lower cost than a higher voltage piece of equipment, noted researcher Ben Ollis of the Power and Energy Systems (PES) group.

SI-GRID got its start as the lab was developing its own microgrid controller, Complete System-Level Efficient and Interoperable Solution for Microgrid Integrated Controls (CSEISMIC), and researchers needed a safe way to test it. CSEISMIC controls the flow of energy between all the components of a microgrid and the larger utility power grid. The test bed was funded by ORNL’s Lab-Directed Research & Development program.

Testing for cyber vulnerabilities

The researchers were surprised at how comparable the characteristics of the low-voltage devices were to high-power devices on SI-GRID. “It’s an order of magnitude difference between the two, but they behave very similarly,” Ollis said.

The low-risk environment of SI-GRID likewise makes it a good platform for testing cyber robustness, Ollis noted. He and his fellow engineers are planning to conduct a cyber wargame exercise on the platform this fall.

Cyberintrusions are a daily reality for utility grid operators battling denial of service, physical system, malicious intent, and authentication attacks. SI-GRID allows researchers to test cyber-physical system (CPS) security and encryption methods against hackers who could try to take control of devices or even completely disable the microgrid, Ollis explained. Identifying vulnerabilities will provide vital information to secure the system.

“The issue for industry, however, isn’t so much that one or two of these distributed generation sources might go down. It’s that a hacker might get into one of these microgrids and gain access to the larger utility network,” Ollis said.

One unique feature of SI-GRID is a reference network that ORNL is working into its microgrid management system that can be used to capture data and verify the operating environment, said Ishita Ray, a University of Tennessee Bredesen Center student working on the project.

The network gathers independent physical measurements and communications data throughout the system and stores them, constantly monitoring traffic. The reference network data can discover patterns, identify vulnerabilities, determine countermeasures, and ultimately devise ways to detect and defend against cyberintrusions. 

Ishita Ray works on the SI-GRID cabinet. (hi-res image)

One of the biggest challenges in setting up the microgrid test bed was in hardware installation, noted PES group researcher Phil Irminger. “You’re not in the ideal world of simulation anymore,” he said. “You’re dealing with wires, physical connections, and sometimes with device failures. If you have an issue, it might be one of 20 different things, from just a loose connection to a blown fuse.”

The greatest successes for the research team have been running the CSEISMIC controller on the SI-GRID and demonstrating how time-sensitive networking (TSN) enhances grid operation, Irminger said.

TSN is a set of standards that provides “time-stamped” synching between devices, greatly enhancing real-time communications. It is especially useful in a system such as a power grid where you may have thousands of connected components. “Those devices are all fighting for bandwidth, and we need to schedule all that traffic so all critical information gets through,” Irminger said. TSN also allows for easier, faster synching between microgrids and the utility grid.

ORNL’s multidisciplinary environment key to success

The researchers credit the multidisciplinary nature of their staff at ORNL for the project’s success. “We have a wide range of expertise—people who know inverter controls and power electronics, people who know data acquisition and are communications experts, as well as staff with expertise in encryption, cybersecurity, optimization, and protection,” Ollis noted. “You need all those different disciplines to be successful with these projects.”

Phil Irminger with SI-GRID components. (hi-res image)
Ollis and Irminger are co-leads on SI-GRID under principal investigator Mark Buckner, leader of the PES group. The co-leads designed the test bed, implemented communications and controls, and oversaw the buildout. Ray has performed much of the physical work on the project, oversaw the architecture of the shadow network, and is currently exploring advanced controls concepts using SI-GRID.

“One of the visions we have for SI-GRID is that it will help create an open ecosystem of collaborative research related to grid modernization, resiliency, and security,” Buckner said. “We want it to serve as an accelerant of innovation, de-risking the transition of ideas and scientific discovery from the lab and academia into actual real-world practice.”

Going forward, the group will continue to work on SI-GRID’s cybersecurity capabilities, study networking of multiple microgrids, and help develop microgrid communications standards. Most grid and inverter devices are proprietary and require individual commissioning, setup, and installation—a lengthy process, Irminger noted. Implementation of a standard that allows for plug-and-play operation would significantly reduce engineering time to commission those devices.

SI-GRID will continue to serve as a research platform at ORNL as scientists refine the CSEISMIC microgrid controller in preparation for real-world testing in Southeast residential community microgrids this fall.

“We want to make this test bed accessible to people who want to do these types of experiments but don’t have the equipment or the time and money to invest in one of their own,” Irminger said. “We could also work with companies to help them set up their own test bed capabilities.”