Grid Contingency Analysis Software Helps Prevent Cascading Failures
High-performance computing tool gives planners a better understanding of the potential impacts associated with extreme events
Two days in the dark, 50 million people without power, 11 dead, and $6 billion in damages. Those were the repercussions of just one blackout in our nation’s history. Cascading failures—similar to what happens when one bulb goes out in a string of lights—have since been the subject of intensive regulation. In fact, power operators face up to $1 million per day in fines by NERC if they don’t comply with mandatory reliability regulations.
That's a lot of pressure. How will they do it?
In partnership with the DOE Office of Electricity Delivery and Energy Reliability and Electric Reliability Council of Texas (ERCOT), researchers at PNNL developed the Dynamic Contingency Analysis Tool, or DCAT. It’s a software package designed for electrical utility companies to understand power instability during extreme events, thus stopping cascading power losses or blackouts. The technology uses cascading failure analyses to screen for weak spots on the grid. Once identified, operators have a greater chance of stopping a cascading domino effect of power loss and planners can reinforce the weak spots of the system.
“We don’t have a crystal ball for utility operators, but we do have DCAT,” said Jeff Dagle, Chief Electrical Engineer at PNNL. “Stopping cascading events before they start gets us a giant step closer to a more reliable electricity grid.”
Putting the “D” in DCAT
DCAT was developed with advanced algorithms and high-performance computing. The computer processing power behind DCAT uses advanced models of the power grid to provide system planners with updated information about the possible risk to the power grid if extreme events were to occur, bridging the gap between utility-grade software and a more complete understanding of electricity reliability for the electricity grid.
Evolving beyond a “steady state contingency analysis” tool, DCAT now provides “dynamic analysis” including the action of protection and control. Overall, the DCAT uses a hybrid dynamic and steady-state approach for simulating the cascading outage sequences that includes fast dynamics and slower steady-state events. It integrates dynamic models with the protection schemes for generation, transmission, and loads. It models special protection schemes as well as other automatic or manual corrective actions that would be implemented during the response to the event.
DCAT, though currently a prototype, is designed as an open platform for public use. It consists of four main modules:
- Model preparation
- Initial system aggregation and event screening
- Dynamic simulation including system protection models
- Post-contingency steady-state analysis
A fifth module is used to process simulation results and log the sequence of cascading events. The software is design to be suitable for high performance computing.
This work was accomplished under a $1.25 million project from DOE and in close collaboration with grid operators, Siemens Power Technologies International, the Electric Power Research Institute, and ERCOT.
“ERCOT was an indispensable partner. They provided critical feedback and collaborated with us on the development of the tool throughout the project,” said Dagle.
PNNL Research Team: Jeff Dagle, Nader Samaan, Yuri Makarov, Ruisheng Diao, Laurie Miller, Francis Tuffner, Mallikarjuna Vallem, Tony Nguyen, Bharat Vyakaranam, Shaobu Wang, and Bei Zhang.