Grid

RamGoss is using innovative device designs and high-performance materials to develop utility-scale electronic switches that would significantly outperform today's state-of-the-art devices. Switches are the fundamental building blocks of electronic devices, controlling the electrical energy that flows around an electrical circuit. Today's best electronic switches for large power applications are bulky and inefficient, which leads to higher cost and wasted power. RamGoss is optimizing new, low-cost materials and developing a new, completely different switch designs. Combined, these innovations would increase the efficiency and reduce the overall size and cost of power converters for a variety of electronic devices and grid-scale applications, including electric vehicle (EV) chargers, large-scale wind plants, and solar power arrays.

Sandia National Laboratories will develop a solid-state circuit breaker for medium to high voltage applications based on a gallium nitride (GaN) optically triggered, photoconductive semiconductor switch (PCSS). During normal operation, the current will flow through high-performance commercial silicon carbide (SiC) devices to achieve high efficiency. When a fault occurs, the fast-response GaN PCSS will be used to break the current. The concept builds on Sandia's knowledge of optically triggered GaN devices, as well as the team's experience in circuit design for MV applications. The GaN PCSS will enable high-voltage operation, potentially scalable from 1 to 100 kV, while achieving superior electrical isolation due to the optical triggering approach. This technology could contribute to more widespread adoption of MVDC power distribution across the grid.

Sandia National Laboratories will develop a new type of switch, a 100kV optically controlled switch (often called photoconductive semiconductor switch or PCSS), based on the WBG semiconductors GaN and AlGaN. The capabilities of the PCSS will be demonstrated in high-voltage circuits for medium and high voltage direct current (MVDC/HVDC) power conversion for grid applications. Photoconductivity is the measure of a material's response to the energy inherent in light radiation. The electrical conductivity of a photoconductive material increases when it absorbs light. The team will first measure the photoconductive properties of GaN and AlGaN in order to assess if they operate similarly to gallium arsenide, a conventional semiconductor material used for PCSS, demonstrating sub-bandgap optical triggering and low-field, high-gain avalanche providing many times as many carriers by the electric field as created by the optical trigger. These two effects provide a tremendous reduction in the optical trigger energy required to activate the switch. The team will then design and fabricate GaN and AlGaN-based photoconductive semiconductor switches. The team predicts that WBG PCSS will outperform their predecessors with higher switch efficiency, the ability to switch at higher voltages, and will turn-off and recover faster, allowing for a higher frequency of switching. Ultimately, this will enable high-voltage switch assemblies (50-500kV) that can be triggered from a single, small driver (e.g. semiconductor laser). These modules will be substantially smaller (~10x) and simpler than existing modules used in grid-connected power electronics, allowing the realization of inexpensive and efficient switch modules that can be used in DC to AC power conversion systems on the grid at distribution and transmission scales.

Siemens will develop an operator support system and grid planning functionality that enable a power system to operate with 100% inverter-based renewable generation from wind and solar. ReNew100 features automatic Controller Parameter Optimization and model calibration technologies that help ensure power system reliability as the generation mix changes. Successful test results will be a milestone toward the goal of a stable and reliable power system obtaining a majority of total electrical energy sourced from variable wind and solar.

Smart Wire Grid is developing a solution for controlling power flow within the electric grid to better manage unused and overall transmission capacity. The 300,000 miles of high-voltage transmission line in the U.S. today are congested and inefficient, with only around 50% of all transmission capacity utilized at any given time. Increased consumer demand should be met in part with a more efficient and economical power flow. Smart Wire Grid's devices clamp onto existing transmission lines and control the flow of power within--much like how internet routers help allocate bandwidth throughout the web. Smart wires could support greater use of renewable energy by providing more consistent control over how that energy is routed within the grid on a real-time basis. This would lessen the concerns surrounding the grid's inability to effectively store intermittent energy from renewables for later use.

Switched Source will develop a power-electronics based hardware solution to fortify electric distribution systems, with the goal of delivering cost-effective infrastructure retrofits to match rapid advancements in energy generation and consumption. The company's power flow controller will improve capabilities for routing electricity between neighboring distribution circuit feeders, so that grid operators can utilize the system as a more secure, reliable, and efficient networked platform. The topology the team is incorporating into its controller will eliminate the need for separate heavy and expensive transformers, as well as the costly construction of new distribution lines and substations in many cases. The power flow controller's low weight and small size means that it can be installed anywhere in the existing grid to optimize energy distribution and help reduce congestion. If successful, implementation of Switched Source's power flow controller will also significantly increase hosting capacity and connectivity for distributed renewable generation. During a prior ARPA-E GENI award, this team developed this platform technology. Now, as an addition to the ARPA-E CIRCUITS program, the team will further its research.

The University of California, Berkeley (UC Berkeley) is developing a device to monitor and measure electric power data from the grid's distribution system. The new instrument--known as a micro-phasor measurement unit (µPMU)--is designed to measure critical parameters such as voltage and phase angle at different locations, and correlate them in time via extremely precise GPS clocks. The amount of phase angle difference provides information about the stability and direction of power flow. Data collected from a network of these µPMUs would facilitate better monitoring and control of grid power flow--a critical element for integrating intermittent and renewable resources, such as rooftop solar and wind energy, and other technologies such as electric vehicles and distributed storage.

The University of Illinois, Urbana-Champaign (UIUC) is developing scalable grid modeling, monitoring, and analysis tools that would improve its resiliency to system failures as well as cyber attacks, which can significantly improve the reliability of grid operations. Power system operators today lack the ability to assess the grid's reliability with respect to potential cyber failures and attacks. UIUC is using theoretical and practical techniques from both the cyber security and power engineering domains to develop new algorithms and software tools capable of analyzing real-world threats against power grid critical infrastructures including cyber components (e.g. communication networks), physical components (e.g. power lines), and interdependencies between the two in its models and simulations.Continuing the project work started by UIUC, Avista Utilities is now developing technology to automatically extract and map electrical switch information to generate cyber-physical models. These cyber-physical models can be used to identify network vulnerabilities as well as identify and prioritize critical assets which will allow utilities and others to conduct simulations, perform analysis, and fortify networks against cyber-attacks.

The University of Michigan will develop load-control strategies to improve grid reliability in the face of increased penetration of DERs and low-cost renewable generation. As the electricity generation mix changes to include more renewables and DERs, load shifting is essential. Today, there are few load-shifting strategies in use at grid scale that are capable of balancing current levels of intermittent energy production. The team will develop three testing environments to identify issues the grid faces with increased levels of energy from distributed and renewable generation. Their method could improve credibility for load-control mechanisms at scale and lower costs to power providers and consumers alike.