Table 4 summarizes OKPUD’s 5 mitigation components with associated programs and activities that support OKPUD’s ongoing commitment to wildfire prevention and mitigation. Not all construction standards, such as underground lines, are employed solely for wildfire mitigation, or installed in all areas of the service territory.
Within these sections, you will find specific information regarding current prevention strategies, lessons learned from the prevention activities, and considerations for the future state.
Table 4. Mitigation Programs & Activities
Design & Construction
Underground distribution lines where practical
Substation perimeter fencing for security and protection
Polymer crossarms
Animal guards on new transformer installations
Avian protection operations manual
Fire-resistant mesh wrap on transmission poles in high-risk areas
Elevated nesting platforms
Steel pole construction in select areas
Covered Jumpers and animal guards on new construction
Vise-top polymer insulators
Electronic reclosers
Inspection & Maintenance
Infrared inspections of substations and large transformers
Substation inspections
Distribution system right-of-way (ROW) maintenance
Transmission ROW Clearing
Vegetation management program
Mid-cycle vegetation trimming
Wood pole intrusive inspection and testing
Brush Clearing around structures
Substation weed control plan
Operational Practices
Community outreach/Controlling incompatible vegetation
Hazard tree removal
Fire suppression equipment on service vehicles
Slip tank trucks used for ignition prevention and support on active fires
Situational Awareness
Weather Monitoring (USFS-WFAS, NWS)
Industrial Fire Protection Level (IFPL) monitoring
Response & Recovery
Outage response communications
Coordination with local first responders
Line patrols prior to re-energization
Regular communication with Washington Dept. of Natural Resources & USFS
7.1 Weather Monitoring
7.1.1 Current Strategy Overview
Situational assessment is the process by which current operating conditions are determined. Situational Awareness (SA) is the understanding of the working environment, which creates a foundation for successful decision-making and the ability to predict how it might change due to various factors.
OKPUD uses various situational awareness resources to monitor evolving fire weather, fuel, and other climatological conditions that may lead to fire events. OKPUD may evaluate information such as Industrial Fire Protection Levels, real-time field observations, GIS data, asset maintenance reports, ongoing wildfire reporting, and other resources. Management staff may also attend local NOAA weather briefings to remain fully informed on upcoming forecast risks. Based on available information, OKPUD appropriately prepares for fire weather conditions as needed.
- The National Weather Service (NWS): The NWS provide on-line predictive fire weather forecasting tools in the form of a current fire-weather outlook, 2-day, and a 3 to 8-day outlook.
NWS Website - NOAA Weather and Hazards Data Viewer: This online map provides historic or real-time surface observations including wind speed and direction, wind gust, dew point, relative humidity, and sea level pressure collected from remote automated weather stations (RAWS). Extreme-weather alerts such as fire weather watch, high wind watch, and red flag warning are provided from this resource.
NWS Weather & Hazards website - Industrial Fire Level Precaution Levels (IFPL): Fire season requirements become effective when fire season is declared in each Washington DNR Protection District.
IFPL website
7.1.2 Industrial Fire Precaution Levels
When conditions of fire hazard exist each summer, Washington Department of Natural Resources, United States Forest Service, or the Bureau of Land Management declare fire season to be in effect. Title 36 of CFR 261.50(a) gives each Forest Supervisor the authority to issue orders which close or restrict use of the area over which he/she has jurisdiction. As conditions warrant, the forester will issue an Industrial Fire Precaution Level4 (IFPL) at 1 of 4 levels. The declaration of fire season affects utility and other commercial operations, and as well as recreational activities by the public. Fire season remains in effect until terminated by each Agency or by reducing the IFPL until conditions for fire hazard no longer exist. OKPUD operates within lands managed by the US Forest Service (USFS) and Bureau of Land Management (BLM). To maintain safety during maintenance and VM work, the Operations Department monitor IFPL levels regularly (during fire season) and directs staff and VM crews to take the necessary precautions and deploy available fire suppression equipment to job sites.
7.2 Fire Response Equipment
OKPUD equip field vehicles with 5-gallon water packs, fire extinguishers, and equipment required by IFPL rules for operating on state and federal lands during seasonal restrictions. The District has also recently acquired a 2300-gallon tanker for pre-watering work sites during fire season. 2 additional seasonally-mounted slip tanks on flatbed trucks provide T6 level water capacity for ignition prevention on work sites.
7.3 Design & Construction Standards
7.3.1 Current Strategy Overview
This WMP integrates and interfaces with OKPUD’s existing operations plans, asset management, and engineering principles, which are themselves subject to change. Future iterations of the WMP will reflect any changes to these strategies and will incorporate new best management practices as they are developed and adopted.
Part of OKPUD’s preventative strategy is to update and leverage their design and construction standards to help mitigate wildfire risks. This is being done currently using fire-averse equipment and material when possible along with new recloser technologies.
7.3.1.1 Overhead vs Underground Conductor
The benefits of overhead conductor is that it is much less costly and much easier to troubleshoot following an outage event, making restoration times shorter compared to underground construction. The downside to overhead conductor is its susceptibility to contact from foreign objects such as wildlife, vegetation, and equipment.
The undergrounding of distribution lines improves reliability in high wind events and functions as an effective mitigation against wildfire. Most new residential subdivision developments are built using UG construction. OKPUD has approximately 506 miles of UG distribution line on its network. While there are many benefits to UG infrastructure, UG lines don’t prevent all outages, and can have their own unique maintenance problems. In rural areas, underground service may be unaffordable, as it requires longer stretches of line per customer and can cost from 4 to 14 times more to install than overhead conductor5.
7.3.1.2 Fire Retardant Pole Wrap
OKPUD is transitioning away from painted protective coatings to a fiberglass-core, fireproof mesh wrap on select transmission poles in high-risk areas. The goal is to improve the resilience of the grid and prevent outages due to range fires that are common in the service area. This material, when affixed to wooden poles, activates within 20 seconds when in contact with wildfire, withstands temperatures up to 2,100°F, and prevents burning, strength loss, and pole failure.
7.3.1.3 Planned Updates
OKPUD will continue to implement fire safety into their design and construction practices. Planned updates include installing avian protection equipment on transformers, reclosers, and dead ends to prevent nesting and birds contacting energized equipment. In the future, new electronic reclosers will incorporate SEL ArcSense and high impedance fault detection (HIF) software as this becomes feasible. OKPUD is also transitioning to metal poles on transmission lines and in selected distribution areas, along with adopting fiberglass arms as the new construction standard, represents a significant upgrade. The use of vise-top polymer insulators and insulating at 25kV are also part of the improvements. To further enhance efficiency, the purchase of a smaller single-axle water truck is being considered for prewatering work areas in fire-prone regions during fire season.
7.1 Fuel & Vegetation Management
When work is well planned and completed, the overall impact on the desirable vegetation on the ROW is reduced, and the neighboring landowners, the motoring public, and the wildlife that uses the ROW for nesting and foraging will benefit. With a prescriptive and balanced approach to VM, OKPUD can focus more of its energy and resources on preparing for future weather events, improving the reliability of the grid, and controlling maintenance costs.
7.1.1 Current Strategy Overview
Trees that grow within or adjacent to powerline right-of-ways (ROWs) are a common cause of outages and damage to facilities, as well as a potential cause for wildfire.
OKPUD maintains over 1,500 miles of overhead T&D ROW to minimize interruptions of services and to provide a safe and reliable supply of electricity to its customers. This includes not only the maintenance of hardware, conductors, and poles but trees and other vegetation that threatens to fall onto or grow into the electrical conductors. To this end, OKPUD has developed a VM program intended to maintain safe and reliable electric facilities, provide safety for the public and for utility workers, and fire mitigation throughout the service area.
Planning considers seasonal and climate considerations. For instance, winter conditions at higher elevations can make it challenging or unsafe to carry out trimming activities due to snow, ice, and cold temperatures. Consequently, crews might limit their work in these areas during winter and instead focus on other zones. In the summer, the Industrial Fire Precaution Levels (IFPL) system imposes restrictions on activities that could ignite fires, particularly in forested or grassland areas. Depending on the fire risk, activities such as using power tools might be restricted during certain times.
Schedules are based around seasonal limitations to optimize efficiency. This involves assessing which areas require immediate attention based on vegetation growth, fire risk, and community needs, and then allocating resources accordingly.
7.1.2 Trimming Standards
OKPUD is authorized by RCW 64.12.035 to trim or remove any tree or vegetation that poses an imminent hazard to the general public or is a potential threat that could damage electric facilities. Trees are trimmed or removed for safety, reliability, board policies, and compliance with the National Electric Safety Code (NESC).
OKPUD’s tree trimming contractors are governed by principles of modern arboriculture using the following standards:
- American National Standards Institute (ANSI) A300 Part 1 concepts and utility directional pruning
- Standard for Arboricultural Operations – Safety Requirements (ANSI Z133-2017)
- OSHA 29 CFR Parts 1910.269
7.1.3 Trimming Schedule
Cycle trimming is the cornerstone of the vegetation management program. Under this concept all system electrical distribution lines are assigned a schedule for tree trimming and/or removal. OKPUD contracted crews are responsible for trimming trees and vegetation to obtain the minimum required clearance with due regard to current and future tree health and symmetry.
To accomplish this, OKPUD contracts full-time tree trimming crews for year-round vegetation management work on a 3-year pruning cycle. Areas with fast-growing species are typically trimmed mid-cycle as needed to maintain safe vegetation clearance from the power lines and associated equipment. Line crews also address vegetation concerns in response to service calls or field observations by employees or customers. Depending on the environmental conditions at any given time, work may be redirected to accommodate limitations from Industrial Fire Protection Levels or winter weather conditions in the higher alpine regions.
7.1.4 Trimming Specifications
OKPUD has an operational and management responsibility to maintain the right of way, under or around its power lines. OKPUD will meet the minimum standards for conductor clearances from vegetation to provide safety for the public and utility workers, reasonable service continuity, and fire prevention.
During tree work, trimmers aim to achieve the clearance specifications described below.
- OH Transmission: Minimum of 10 feet for from the outside conductor
- OH Distribution: Minimum of 6 feet for from the outside conductor
- Trees Under Conductors: Removal is preferred, otherwise 12 feet below the conductor.
- Overhanging Branches: Removed to a height of 15 feet above all distribution conductors and all branches over transmission conductors. All weak, diseased, and dead limbs above the conductors shall be removed.
- Secondary/Service Wire: Trees interfering with secondary voltage insulated, duplex or triplex secondary lines will not be trimmed by Okanogan County PUD tree trimming crews, as it is the customer’s responsibility to maintain secondary lines.
- Pole Clearing: Vines growing on poles and guy wires shall be cut at ground level to a 3-foot circumference.
- Brush Removal: In residential or maintained areas, tree limbs resulting from crew activities are typically chipped and removed from the site. Large tree limbs and logs greater than 6 inches in diameter are left onsite. Worksites will be left in a safe and orderly condition.
7.1.5 Vegetation Control Options
Methods for controlling vegetation along the ROW include chemical, biological, manual, or mechanical techniques. The choice of control option(s) is based on effectiveness, environmental impact, site characteristics, worker and public health, and safety concerns.
7.1.6 Hazard Tree Removal
A subset of Danger Trees6, a Hazard Tree is defined as any tree or portion of a dead, dying, rotten, or decayed tree that may fall into or onto the overhead primary lines, or trees leaning toward distribution facilities. OKPUD makes it a priority to remove hazard trees as soon as they are identified using the district’s Vegetation Program as a general guideline.
Tree removal eliminates hazardous conditions, improves access to facilities, and reduces future work and will be pursued wherever feasible. Hazard trees are typically removed only when there is a threat of the tree or limbs failing and contacting transmission or primary conductors. While tree removal requires signed permission from the property owner, ROW easements or permits may have already granted permission for tree removal, in which case the property owner is notified.
Hazard tree removals are assessed and completed as part of the normal cycle trim. These trees are generally outside the right-of-way and are deemed by an Arborist to pose a potential threat to the lines. This is especially important in those areas that have had previous fires where dead or dying trees could fall on conductors or become fuel for a new fire event. Leaning trees beyond the ROW which would strike the power line in falling, and which would require topping if not removed, shall either be removed or topped.
Tree removal candidates include the following:
- Fast-growing trees that interfere with primary conductors
- Deciduous trees that require excessive trimming
- Dead, dying, or defective trees that have a high probability of falling and contacting the primary conductors
- Trees with tree houses or climbable trees in close proximity to transmission or primary conductors
- Naturally seeded trees or smaller trees that will eventually interfere with primary conductors
7.1.7 Herbicide Treatment
Twice a year, the OKPUD contracts for the application of soil sterilization herbicides to eradicate vegetation in substations, pole yards, and various other locations throughout Okanogan County. This includes noxious weed and insect control. Herbicides or chemicals may only be used with authorization from the District ROWS.
All soil sterilization work at substations must be completed between April 1st and May 1st for spring applications, and between September 1st and November 1st for fall applications. The scheduling is at the discretion of the District. The District requires that 1 qualified District employee be present as an observer and to provide access to locked areas in substations.
7.1.8 Brush Mowing
The brush mowing process is used to remove undergrowth within the OKPUD ROWs. Brush and small trees are removed with a large tractor-mounted shredder that cuts and mulches the undergrowth into small pieces and spreads them across the ROW. The result is a ROW that is resistant to fire and easy to navigate by repair crews. This work is prioritized in areas identified as having high fire risk where access to lines may be difficult.
7.2 Asset Inspections & Responses
7.2.1 Current Strategy Overview
Recognizing the hazards of equipment that operate high-voltage lines, OKPUD maintains formal time-based inspection and maintenance programs for distribution and substation equipment, which plays an essential role in wildfire mitigation, reliability, and safety.
Recognizing the hazards of equipment that operate high voltage lines, OKPUD asset inspections include:
- Time-based inspection for wood poles
- Monthly substation inspections
- Annual infrared/FLIR substation inspections
7.2.2 Pole Management Program
To maintain OKPUD’s utility poles, a Pole Management Program was initiated with the goal of inspecting approximately 10% of the poles per year. Contracted pole testers perform the pole inspections on a planned basis to determine whether they have degraded below National Electric Safety Code (NESC) design strength requirements with safety factors.
Poles up to 9 years old will undergo a visual inspection with no further action unless necessary. Poles that are 10 years and older will be inspected both above and below the ground. All inspection findings are recorded and maintained by OKPUD.
Qualified contractors will handle all aspects of the inspection and treatment process, including supervision, labor, tools, equipment, data collection devices, transportation, and materials. A visual inspection of all poles shall be made from groundline to the top of the pole. The pole will be inspected for issues per the District-provided overhead facilities inspection form.
OKPUD provide the necessary specifications and maps to guide the contractors in locating and servicing the poles. If the pole inspection results in the rejection of the pole, the pole will be photographed and marked for replacement or reinforcement.
7.2.3 Infrared Thermography
Hundreds of different pieces of equipment may be found in an electrical distribution system. They start with electricity production, high voltage distribution, switchyards, and substations, and end with service transformers, switchgear, breakers, meters, local distribution. Abnormal heating associated with high resistance or excessive current flow is the main cause of many problems in these electrical systems.
Using FLIR cameras, also referred to as IR thermography, OKPUD inspects its substations to locate hidden electrical and mechanical issues before they become a reliability issue. FLIRs
7.1 Workforce Training
7.1.1 Current Strategy Overview
OKPUD has developed rules and complementary training programs for its workforce to reduce the likelihood of an ignition. All field staff are:
- Trained on the content of the WMP
- Trained in proper use and storage of fire extinguishers
- During pre-job briefings, to discuss the potential(s) for ignition, environmental conditions
- Required to identify the closest fire extinguisher and other fire abatement tools
- Required to report all ignition events to management for follow-up
- Attend an RT-130 Wildland Firefighting Training annual refresher.
7.2 Relay & Recloser Policy
7.2.1 Current Strategy Overview
It is not a current practice to configure reclosers with alternate settings.
7.3 De-energization / Public Safety Power Shutoff
7.3.1 Current Strategy Overview
A Public Safety Power Shutoff (PSPS) preemptively de-energizes power lines during high wind events combined with hot and dry weather conditions. OKPUD has considered the extremely complex external risks, and potential consequences of de-energization while striving to meet its main priority of protecting the communities and customers we serve. They include:
- Potential loss of water supply to fight wildfires due to loss of production wells and pumping facilities.
- Negative impacts to emergency response and public safety due to disruptions to the internet and mobile phone service during periods of extended power outages.
- Loss of key community infrastructure and operational efficiency that occurs during power outages.
- Medical emergencies for members of the community requiring powered medical equipment or refrigerated medication. Additionally, the lack of air conditioning can negatively impact medically vulnerable populations.
- Negative impacts on medical facilities, fire, police, and schools.
Traffic congestion resulting from the public evacuation in de-energized areas can lengthen response times for emergency responders.
- Negative economic impacts from local businesses forced to close during an outage.
- The inability to open garage doors or motorized gates during a wildfire event.
- Loss of power for fuel station pumping
The risks and potential consequences of initiating a PSPS are significant and extremely complex. Based on the above considerations, OKPUD reserves the option of implementing a PSPS when conditions dictate but does not currently plan to proactively de-energize its system. On a case-by-case basis, the OKPUD will consider de-energizing a portion of its system in response to a known public safety issue or response to a request from an emergency management agency. Any de-energizing of the lines is performed in coordination with key local
partner agencies, but the final determination is made by OKPUD.
5 Underground vs. Overhead: Power Line Installation-Cost Comparison and Mitigation; CPU Underground Programs
6 As defined by ANSI 300 Part 7 standards