Fighting Fire With ... Data, A Conversation with Tom Rolinski, SCE Fire Scientist
image credit: SCE weather station by author
- Jan 14, 2020 3:00 pm GMT
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Southern California Edison’s (SCE) electrical system encompasses approximately 52,000 circuit miles of transmission and distribution overhead powerlines. More than 14,000 of those circuit miles, with approximately 340,000 associated transmission and distribution pieces of equipment, traverse what are designated as High Fire Risk Areas (HFRA). HFRA are areas in SCE’s 50,000 square mile service territory where there is an elevated hazard for the ignition and rapid spread of fires associated with electrical equipment due to strong winds, abundant dry vegetation, and other environmental conditions. HFRA represents more than a quarter of the SCE service territory and cover a variety of terrains and biomes.
In 2017 and 2018 eight of the 20 most destructive wildfires in California history occurred. The increase in wildfire risk and occurrence is due to climate change, drought, increased development in the wildland-urban interface and a build-up of fuel. While not the only, or the greatest cause, utility equipment failure has been identified as the likely cause in some of the largest wildfires that occurred in those years. As has been discussed in other articles in this forum, Pacific Gas & Electric (PG&E) has entered bankruptcy as a result of their liability, primarily for the Paradise fire. SCE’s equipment was identified as the likely cause in the Thomas fire, although SCE believes the ignition at Anlauf Canyon, the origin of that fire, started at least 12 minutes prior to any issue involving SCE’s system and at least 15 minutes prior to the start time indicated by the Ventura County Fire Department. During the period 2015-2017, 92% of reportable ignition events in SCE’s service territory were associated with overhead distribution equipment. Fifty percent of the reportable events occurred within HFRA.
In response to the increased risk and occurrence of wildfires, California Senate Bill 901 incorporated new provisions into the California Public Utilities Commission (CPUC) Public Utility Code Section 8386 requiring California utilities to develop, submit and implement annual wildfire mitigation plans. SCE has submitted their 2019 Wildfire Mitigation Plan (WMP) which specifies various actions SCE is taking and will take to mitigate the risk of wildfires occurring as well as their response when wildfires do occur. This includes:
- System hardening
- Reconductoring and installation of branch line fuses and current limiting fuses in HFRA
- Replacing transformers containing mineral oil with those containing ester fluid
- Installing covered conductor
- Replacing current automatic reclosers with remote controlled automatic reclosers and fast curve settings
- Replacing wood poles with fire resistant poles as needed during installation of covered conductor
- Expanded vegetation management
- Enhanced situational awareness through:
- Installation of micro weather stations and HD cameras across HFRA
- Development of a high-resolution weather model
- Enhanced meteorology capability
- Acquisition of a high-performance computing platform for fire potential index modeling
Additional personnel resources, including a Fire Scientist position, are also identified in the plan. The WMP defines the Fire Scientist role as helping to “build and mature complex fire models designed to predict wildfire ignition and propagation by considering multiple variables such as weather, fuel, and asset conditions.”
To find out more about the role of the Fire Scientist and how data, such as that provided through the situational awareness capabilities, is used in mitigating fires I had a conversation with Tom Rolinski, SCE’s Fire Scientist. Unlike the typical firefighter armed with a fire hose, maybe an axe or a shovel or flying a helicopter or plane with fire retardant, in his role as Fire Scientist, Rolinski is armed with data, analytics software and high-performance computing power. Rolinski extends the definition of his role in the WMP to “responsible for bringing together the latest science and technology to help with wildfire mitigation by building a fire science program which includes weather stations, hi-def cameras, fire spread modeling with simulations on demand (real time and out to 3 days). Also modeling past events to see which assets are most likely to start fires and which should be de-energized.”
A major environmental phenomenon related to wildfire in Southern California is what are called Santa Ana Winds. These winds occur from September through May with the fall months typically presenting the greatest wildfire danger. Forecasting these winds as well as their potential to cause wildfire is vital. While working for the US Forest Service (USFS), Rolinski collaborated with others from San Diego Gas and Electric (SDG&E) and the University of California Los Angeles (UCLA) to develop the Santa Ana Wildfire Threat Index (SAWTI https://fsapps.nwcg.gov/psp/sawti/). This index provides more classifications than the National Weather Service’s (NWS) Red Flag Warning (RFW) and requires additional data to calculate the index. When the SAWTI shows elevated conditions and/or there is an NWS RFW, SCE will initiate their Fire Prevention Plan (FPP).
The SAWTI is determined based on two components. The first component is the weather data. The wind variable is what is primarily noted during a Santa Ana Wind event and it is a primary factor. The SAWTI team also identified the amount of dry air present near the surface, or dewpoint depression, as another significant variable contributing to large fire potential. The other component is the fuel moisture component which is comprised of three variables. These variables are the dryness of dead fuel, the live fuel moisture content and the state of green-up of annual grasses. Based on a predictive model utilizing this data, four levels of threat (MARGINAL, MODERATE, HIGH and EXTREME) are identified.
At SCE, Rolinski has extended this concept utilizing the high-performance computer cluster (HPCC) that has been acquired to produce the internal Fire Potential Index (FPI). While the Santa Ana winds and therefore the SAWTI cover a large percentage of the SCE HFRA, the FPI will also address areas not covered by the SAWTI. SCE utilizes vendors to obtain the fuel moisture variables for those areas not covered by the SAWTI.
In 2019 Rolinski and SCE continued the development of the FPI by adding more granular weather data and integrating historical weather data. This allows for the determination of the potential for fire activity at a circuit level. This level clarifies the need for de-energization of circuits or segments of circuits to reduce the fire potential resulting in Public Safety Power Shutoffs (PSPS) which received much notoriety in California during the last year.
The HPCC used for the FPI will also be used to run fire spread models which will look at the potential risk of past, current and future event scenarios. The HPCC will store weather and fuel conditions for a 30-year period to provide the basis for analysis of wildfire behavior in support of predictive models.
Providing data to Rolinski and SCE’s meteorologists are the weather stations which are being installed. As of November 2019, 470 of the planned 850 weather stations have been installed. The weather stations provide observed wind, relative humidity, and temperature values. The data from the weather stations enhance a high-resolution weather model and provide real time data near circuits in HFRA. The meteorologists develop comprehensive weather forecasts starting 4-7 days in advance of any predicted severe weather event. These forecasts are used to plan mitigations for potential wildfire events.
In addition to the data being used by Rolinski and the meteorologists, SCE is also collecting further data as part of their inspection programs. Overhead distribution lines within HFRA are being inspected utilizing infrared (IR) camera technology. The IR program identifies “hot spots” on distribution system equipment that indicate potential equipment failures. This data is utilized to prioritize work on the identified equipment.
SCE has also expanded it vegetation management program to identify trees within HFRA that could fall into or otherwise affect overhead distribution lines based on their structural condition. Given that wind may blow tree limbs a considerable distance, trees up to 200 feet away for the lines are assessed. Identified trees are then scheduled for removal or trimming as appropriate.
In addition to the internal use of data for fire mitigation, SCE is also sharing data with external agencies including local governments in their service territory and with state agencies such as the Department of Forestry and Fire Protection (CAL FIRE), the Office of Emergency Services (OES) and the CPUC. The data provides information such as the general location of infrastructure, outage maps and vegetation databases.