After several wildfires caused major damage to San Diego Gas & Electric Co.'s (SDG&E) electrical system in 2007, the utility developed a Community Fire Safety Program to enhance power line safety, mitigate fire risk, increase system reliability and help the region's overall emergency preparedness.
Over the last five years, the utility has made significant enhancements in system design, operational procedures, and supplemental inspection and maintenance practices. SDG&E implemented these changes to increase safety and to reduce the potential for electrical facilities to be an ignition source for wildland fires. The company, which supplies energy service to 3.4 million consumers through 1.4 million electric meters and more than 850,000 gas meters, continues to focus on reducing fire risk throughout its 4,100-sq-mile service area.
Educating the Community and the Workforce
One of the first efforts SDG&E undertook to reduce fire risk was community outreach and education. Today, the San Diego utility partners with 53 fire agencies, fire safe councils, Community Emergency Response Teams (CERTs) and other community organizations. For example, the American Red Cross, 2-1-1 San Diego and the Burn Institute provide resources and information on disaster preparedness and living with fire danger.
The utility also invited its customers and community leaders to participate in a fire safety collaboration process. About 40 stakeholders — representing local schools, water districts, disability rights advocates, consumer groups and fire departments, among others — worked with SDG&E for more than a year to develop a joint fire-prevention plan. The process was facilitated by a federal mediator. The outcome: the group proposed more than 100 potential solutions to help prevent major fires.
SDG&E already is implementing many of the solutions identified by stakeholders, such as turning off reclosers, hardening its overhead electrical system through the use of steel poles and larger conductor, and undergrounding portions of the system where feasible.
In addition to working with regional stakeholders on fire-prevention measures, SDG&E has trained every employee and contractor involved in day-to-day operations on fire prevention and fire suppression. Further, the company has outfitted its vehicles with light-duty fire-suppression equipment, such as shovels and small water pumps, so field crews have the tools to extinguish a spot fire, if necessary.
Enhancing Vegetation Management
SDG&E also has reduced its fire risk by increasing tree trimming and brush clearing in high-risk fire areas. For example, it has increased the frequency of its tree inspections and hazard tree evaluations. In addition, recent regulatory changes have increased minimum clearance requirements between trees and power lines in the Fire Threat Zone (FTZ), thereby requiring greater clearances at time of trim.
SDG&E maintains clearance for more than 400,000 trees near power lines; nearly 100,000 of these trees are located in the Highest Risk Fire Area (HRFA). The HRFA was determined using Cal Fire data and is defined as the area within SDG&E's service territory where the combination of potentially high winds, vegetation and overhead facilities create the most critical fire hazard.
Compounding the challenge, more than 16,000 wood poles within the HRFA have “non-exempt” equipment, which means they represent a potential fire-ignition risk. As a result, SDG&E crews routinely must clear away the brush from the base of these poles to mitigate the fire risk. The company is replacing some non-exempt equipment, where feasible, with more fire-resistant equipment.
In acknowledgement of the utility's extensive vegetation management efforts, the National Arbor Day Foundation has named SDG&E a Tree Line USA utility for 10 years in a row for demonstrating “best practices in utility arboriculture.”
Revising Rules for Overhead Lines
Regulatory changes also have been a factor in SDG&E's success with fire prevention. With SDG&E's urging, the California Public Utilities Commission (CPUC) initiated an Order Instituting Rulemaking (OIR) to improve fire safety statewide. To date, SDG&E has implemented the OIR Phase 1 enhancements, such as increasing the minimum vegetation clearance for the area of San Diego County deemed by Cal Fire to be the FTZ. Cal Fire is the statewide fire agency responsible for fire protection in largely rural, state responsibility areas. The company is also increasing the frequency of patrol inspections for electric distribution circuits in the FTZ. Further, the CPUC ordered communications infrastructure providers (CIPs), whose equipment is attached below the power lines on utilities' poles, to perform patrol inspections. Those inspections were completed by the CIPs Sept. 30, 2010.
On Jan. 12, 2011, the CPUC approved the safety OIR Phase 2 enhancements, which included adding pole-loading criteria as well as clarifying vertical clearance requirements. Phase 2 also required additional patrol requirements for CIPs.
Hardening the System
Since 2007, SDG&E has implemented transmission system hardening projects such as replacing wood poles with steel poles and installing stronger multistranded steel core conductors. The company has increased vertical and horizontal spacing of conductors, and its steel structures are designed to withstand higher wind speeds. To date, the utility has invested about $200 million to replace more than 1,650 transmission wood poles with steel. Over the next five years, SDG&E plans to invest more than $900 million to harden all transmission lines currently on wood poles in the FTZ. In addition, SDG&E now also is focusing its hardening efforts on its distribution equipment. Since February 2011, all new and replacement distribution poles in the FTZ must be steel. To date, SDG&E has installed or replaced more than 850 distribution poles.
SDG&E has expanded its inspections of overhead lines, poles and associated equipment. In 2009, SDG&E inspected 60,000 power poles in the FTZ, looking for conditions that could create a fire-ignition risk and made necessary modifications. The ongoing special inspections are done every three years, even though the required inspection cycle is five years.
The company is using smart technology to reduce fire risk. For example, SDG&E has installed more than 160 S&C Electric IntelliRupter PulseCloser switches to protect lines. The utility also has acquired and analyzed LiDAR laser-scanning data for every transmission line and structure in the HRFA to identify potential clearance issues. In addition, SDG&E has notified the third-party utilities (CIPs) that have equipment attached to its poles when there are conductor clearance violations and has followed up to make sure the CIPs have made the necessary corrections.
The utility has completed undergrounding of several segments of lines in the HRFA and plans to do more in the future. In fact, in its General Rate Case, which will establish funding levels for the next four year, SDG&E requested approval of funding for the conversion of selected overhead facilities to underground as part of its continued focus on making its system more fire safe.
SDG&E, in an ongoing project, has analyzed, developed plans and taken action to harden selected long spans of conductor, adding specialized equipment designed for improved fire safety. These include Fault Tamer fuses, a type of fuse that doesn't expel any parts or sparks during a circuit interruption, as well as wireless fault indicators to better support visibility of faults on the electrical system.
Creating Enhanced Response Measures
In addition to hardening its electrical system, SDG&E brings in contract firefighters to serve as a Utility Wildfire Prevention Team to accompany SDG&E crews during high fire-risk conditions to provide immediate fire suppression in case of a utility-caused ignition. Contracts for 2010 and 2011 covered transmission and distribution activities and staffed up to eight fire engines and crews. For 2012, similar contracts are in place and are being implemented. This approach provides early fire detection and rapid response because the team is on standby during hazardous fire weather conditions. The company also can deploy the team during outage restoration or other work on power lines.
Another way SDG&E can respond quickly to emergencies is with its Erikson Air-Crane S64F helitanker, also known as the “Sun Bird.” This heavy-lift helicopter plays a dual role by assisting with the construction of SDG&E's 500-kV Sunrise Powerlink project as well as fire suppression. The utility has entered into cooperative agreements with local fire agencies — both city and county — to use this helicopter as needed. The Erickson Air-Crane has a 2,500-gallon tank, a 2,000-gallon bucket and a refill capability of just 50 seconds, which gives fire agencies additional support for initial attack.
In September 2010, at the request of Cal Fire, SDG&E dispatched the helitanker to the Cowboy Fire in east San Diego County, where it made 62 water drops totaling 87,000 gallons, or enough water to fill 174 fire trucks. This was a successful integration of the giant bird with other air attack efforts on the fire. A similar Erickson Air-Crane helicopter, which SDG&E had leased for power line construction, was sent to help fight the Eagle Fire over five days in July 2011. During this event, the utility's helitanker made 356 water drops, which equaled 178,000 gallons.
SDG&E also has developed a dedicated staff of five fire coordinators, all of whom have long-term experience as fire chiefs with state, federal and local fire agencies. Their role in the utility is to coordinate training and also respond to fires throughout its service territory. Among other fire-prevention-related activities, they educate and train SDG&E linemen on how to respond safely to substation, transformer and oil fires. SDG&E has also formed a Reliability Improvement Team to focus on overall fire-risk reduction in the HRFA.
SDG&E's Weather Station Network
SDG&E continues to manage its weather station network (see “Linemen Deploy Smart Grid Technology,” T&D World, September 2011). The company employs two meteorologists to monitor and forecast potentially hazardous weather conditions to improve its operational readiness. So far, the utility has installed at least one SDG&E-owned and -operated Campbell Scientific anemometer weather station on every circuit in the HRFA, with redundant communications via cellular and SCADA connections. The utility also continuously monitors existing Remote Automated Weather Stations within the service territory.
With these kinds of additions, SDG&E now owns and operates the third-largest and the densest nongovernmental weather network in the United States. SDG&E has 128 fixed weather stations as well as eight portable weather stations, which report weather data every 10 minutes, for a total of 130,000 data points daily, providing real-time information for operations, forecasting ability and research. SDG&E makes this data available to the public via the National Oceanic and Atmospheric Administration to support research, the community and first responders. SDG&E also has six back-country weather cameras that stream live video back to a central control center where operators can see the actual hazardous weather conditions for better operational decision making.
Putting the Plan to the Test
SDG&E has implemented many proactive measures to enhance public safety and, as a result, was able to manage the 2011 fire season without any significant events. The utility's prevention strategies were tested, however, during a Red Flag Warning event Nov. 2, 2011.
SDG&E activated its Emergency Operations Center to prepare and monitor the forecasted dry, windy conditions. The utility contacted about 11,500 customers in the areas where the winds were expected to be strongest to alert them of the weather conditions and to advise them the utility could shut off the power for public safety if the winds exceeded system design limits. In the end, it wasn't necessary to de-energize any lines.
SDG&E staged crews, troubleshooters and contract firefighting crews in those areas to shorten response time. The wind during the event gusted up to about 50 mph in the northeast portion of SDG&E's service territory around the Rincon Reservation. There were no SDG&E-related fires during this Red Flag Warning, a testament to the utility's comprehensive fire-prevention measures and its commitment to public safety, customer service and reliability.
SDG&E has made significant progress in reducing systemwide fire risk, but recognizes there still could be other opportunities for improvements to add to its fire-preparedness program. A team of employees across various departments of the organization continues to meet biweekly to discuss ways to improve community outreach, customer education and communication; to explore best practices in vegetation management, system hardening and enhanced response measures; and to find opportunities to expand the SDG&E weather station network and/or add new technologies to further improve situational awareness.
Lena Fotland (firstname.lastname@example.org) is a project manager in electric distribution operations for San Diego Gas & Electric. She has been with the company since 2000.
2-1-1 San Diego | 211sandiego.org
American Red Cross | www.redcross.org
Arbor Day Foundation | www.arborday.org
Burn Institute | www.burninstitute.org
Campbell Scientific | www.campbellsci.com
Erickson Air-Crane | www.ericksonaircrane.com
San Diego Gas & Electric | www.sdge.com
S&C Electric Co. | www.sandc.com