It is so ironic that an IEEE paper was published in July of this year entitled ‘Hurricanes and Power System Reliability—The Effects of Individual Decisions and System-Level Hardening’1
Of course, there were many previous papers on this topic, and I have not delved much into the architecture Puerto Rico’s Power Distribution infrastructure (but I will in the near future on EDN in an in-depth tech article); however, I just want to briefly discuss the importance of a system with integrated outage-prediction and an agent-based model to help in system-level hardening.
Power was widely available in Puerto Rico before Maria hit, even isolated rural villages had power and fresh water. The island was self-sufficient in producing its own power. The island generated 98 percent of its electric power from oil, with coal and hydroelectric power accounting for the remainder. PREPA, the Puerto Rico Electric Power Authority, is the only distributor of power on the island.
PREPA's power plants are an average of 44 years old; the industry-wide average is 18 years.
The island gets most of its power from Venezuelan oil, and PREPA relied on selling bonds to pay for the imported oil it burned at its aging power plants that needed billions of dollars of repairs.
Some new design architectures will need to be called upon in re-building the island’s power infrastructure. These can be simple things like raising sub-stations (this could work for flooding, but they had better be built from concrete and steel for hurricanes), underground power lines (I like this), and possibly replacing power utility poles that could withstand greater wind forces (I’m not fond of that one in light of this year’s hurricane force winds)
Reference 1 is unique in its treatment of this problem in that it closes the feedback loop in power utility modeling by including customer behavioral response. That means having an integrated power outage prediction model as well as an agent-based model which would use a probabilistic and consistent synthetic hurricane generation model which could create a tunable hurricane environment. Local social science studies of Puerto Rico resident’s behavioral responses to natural hazards need to be included in this model. However, Puerto Rico must first and foremost, build a sustainable, reliable infrastructure and then possibly implement such a software model.
Reference 2 discusses more of the system infrastructure hardening aspects of this problem and uses the prediction and design model to help build a strong physical infrastructure via that model which will simulate strong winds such as were seen in this year’s hurricanes.
Reference 2 looks at critical components in a power system infrastructure and the fact that system breakdowns occur due to two, independent and competing random failures: that of maximum deterioration of that component and failure caused by a hurricane or other natural disasters—-Puerto Rico unfortunately had both of these events occurring at the time of the hurricane Maria strike.
In the prediction side of things, Poisson processes are used to describe things such as El Nino/La Nina effects on hurricane arrivals or hurricane arrival rates. A MATLAB algorithm is run for different scenarios
A recent Edison Electric Institute study indicated that “infrastructure hardening should not come only as a result of storm damage and teardowns, but as part of a regular maintenance schedule.” By hardening, Reference 2 means any strategy that makes the infrastructure statistically more resistant against hurricanes.
We pray for the Puerto Rico people as well as all other victims of this year’s natural disasters of hurricanes and earthquakes. But in addition to our prayers, concerns and donations—engineering needs to step into the forefront of this process and citizens need to demand that local authorities find a way to fund and finance such system re-designs and predictive modeling.
1 ‘Hurricanes and Power System Reliability—The Effects of Individual Decisions and System-Level Hardening’, A.C. Reilly, G.L. Tonn, C. Zhai, S.D. Guikema, Proceedings of the IEEE, Vol. 105, No. 7, July 2017 (This paper is available on IEEE Xplore and can be accessed by subscribing to this site)
2 System Hardening and Condition-Based Maintenance for Electric Power Infrastructure Under Hurricane Effects Ali Arab, Eylem Tekin, Amin Khodaei, Senior Member, IEEE, Suresh K. Khator, and Zhu Han, Fellow, IEEE; IEEE TRANSACTIONS ON RELIABILITY, VOL. 65, NO. 3, SEPTEMBER 2016