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HomeMy WebLinkAboutTDPUD Vegetation Management Plan July 2018 Vegetation Management Program Revised: July 2, 2018 1 INDEX Section Page Introduction 2 Service Area 2 Program Description 2 Regulatory Requirements 3 Clearance Requirements 5 Program Personnel 6 Program Operation Elements 6 2 VEGETATION MANAGEMENT PROGRAM Truckee Donner Public Utility District Mission Statement – District Code, Title 1, Section 1.05.010 The Mission of Truckee Donner Public Utility District is to provide reliable, high quality water and electrical power services while meeting customer demand, and to manage District resources in a safe, open, responsible, environmentally sound manner at the lowest practical cost. Introduction The District has a responsibility to maintain vegetation so as not to threaten the safety and integrity of electric facilities. The District's Vegetation Management Program (the Program) is an important part of the District's effort to deliver safe, reliable and cost-effective electric service to customers. The goals of the Vegetation Management Program include: (1) ensuring the safety of District linemen and the general public, (2) reduction of fire risks due to tree contacts or electrical sparks igniting brush, (3) the prevention of customer outages due to tree contacts, and (4) aesthetics. The Program is designed to meet the goals and objectives of the District, as well as State and Federal requirements, as they relate to electric utility right-of-way maintenance. Service Area The District is a Public Utility District of the State of California engaged in the distribution, sale and delivery of electric power and energy. The District is a transmission-dependent utility connected to NV Energy’s system and is located high on the e astern slope of the Sierra Nevada. The District is not interconnected with any other utility. The District's electric service territory is comprised of approximately 44 square mi les in eastern Nevada County and approximately 1.5 square miles in adjacent Placer County. The electric system includes approximately 135 miles of 12.47 kV and 14.4 kV overhead distribution lines, and about one- half mile of 60kV overhead transmission line s. Program Description The District is required by State and Federal law to prune or remove vegetation close to energized electrical facilites for public safety and electric system reliability. The District adheres to all applicable vegetation clearance requirements and performs regular vegetation managment in accordance with State and Federal requirements, industry standards, and other procedures that help to prevent outages and fires due to tree contact. Vegetation management generally consists of rout ine inspection, trimming, pruning, felling, and/or removal of trees, bushes, shrubs, vines, and other vegetation within overhead electric rights- of-way. 3 Vegetation removal is performed by mechanical trimming in and around transmission and distribution line circuits rights-of-way, from substations to the end of the circuits. An emphasis is placed on the removal of tree branches and trees that are located within clearance limits, ground-level clearing around poles that contain transformers and switches, plus the removal of hazard trees that may be located inside or outside of the right-of-way. The District does not perform vegetation removal operations in the following areas: 1. Supply Service Drops Supply service drops, or service wires, are defined as the overhead conductor from the District’s distribution pole line to the customers’ service entrance or meter base equipment. These overhead supply lines are generally energized at 240 volts. The District does not perform vegetation management operaions along s upply service drops. Tree triming and maintaining the health of trees on private property is the customer’s or property owner’s responsibility. The customer or property owner must maintain a minimum 2 foot clearance f rom supply service drops to trees and other vegetation. Upon request, and during normal business hours, the District will temporarily de-energize or remove the customer’s overhead secondary service line at no charge to the customer, thereby allowing for tree trimming or maintenance work to be performed safely. 2. Padmounted Equipment In areas served by underground electric facilities, padmounted equipment, including transformers and switchgear, are placed at customer locations or select intervals along main electric lines near streets and roads. District employees must be able to access this equipment at any time for routine maintenance, troubleshooting, or emergency repairs. This equipment must be visually and phyisically accessable to District crews at all times. A clear working area must be maintained on all sides of padmounted equipment. The door side shall have a 10 foor minimum clear working area. The non-door sides shall have 3 foot minimum clear working area. Clear working area shall mean no fences, shrubs, trees, landscape rocks or other obstructions. The customer or property owner must maintain these clear working areas for District access. Regulatory Requirements The District performs vegetation managment in accordance with State and Federal requirements. In addition, the District follows industry standards, and other procedures that help to prevent outages and fires due to tree contact. These requirements, standards, and procedures include:  California General Order No. 95, Rule 35 – Vegetation Management This rule specifies the minimum radial clearance that must be maintained at all times from energized conductors to vegetation. 4  California General Order No. 95, Appendix E – Guidelines to Rule 35 This rule specifies the minimum radial clearance that must be maintained from energized conductors to vegetation at time of trimming.  California General Order No. 95, Rule 21.2 D – High Fire Threat District This rule specifies the use of California Public Utility Commission (CPUC) Fire Threat Map to identify fire threat level zones.  CPUC Fire Threat Map This is the CPUC’s statewide Fire Threat Map identifing areas of the state at an elevated (Tier 2) or extreme (Tier 3) risk of power line ignitied wildfire.  California Public Resources Code Section 4292 This law is administered by the California Department of Forestry and Fire Protection (CALFIRE). The law requires the maintenance of a 10 foot radial firebreak around electric utility poles that contain switches, fuses, transformers, or other electric equipment.  California Public Resources Code Section 4293 This law is administered by CALFIRE. The law specifies th e minimum clearance between energized conductors and vegetation. It also requires the removal of dead, deseased, or dying trees, or trees that could fall into electric lines . Such trees may be located inside or outside of the right-of-way or easement areas.  California Administrative Code, Title 8, Article 37 - Proximity to Overhead Lines This code specifies minimum clearances between personnel and equipment working in close proximity to overhear electric facilities.  California Administrative Code, Title 8, Article 38 - Line Clearance Tree Trimming Operations This code specifies requirements for personnel performing line clearance tree trimming operations.  California General Order No. 165 – Inspection Requirements for Electric Distribution and Transmission Facilities This rule specifies the minimum cycle times for inspection of electric distribution and transmission lines.  ANSI A300.1 – Tree Care Operations - Pruning This national standard addresses pruning practices for tree trimming operations.  ANSI Z133 - Standard for Safety Requirements in Arboricultural Operations This national standard addresses arboriculture safety requirements for pruning, repairing, maintaining and removing trees, and for using equipment in such operations. 5  OSHA 29 CFR 1910.269 - Electric Power Generation, Transmission, and Distribution This federal standard specifies requirements for worker safety in the electric power industry.  ISA Best Management Practices – Vegetation Managment The International Society of Arboriculture (ISA) developed this BMP for the selection and application of methods and techniques for vegetation control for electric rights -of- way.  District and other standards as referenced in this document. Clearance Requirements The following table reflects the District’s current minimum clearances required between conductors and trees: Clearance of Conductor to Vegetation Trimmed Minimum Type of Conductor Voltage Clearance Clearance Secondary Supply 0 to 750v 4 ft. 2 ft. Conductors Primary Supply Conductors 750v to 22,500v 12 ft. (1., 3.) 4 ft. (2.,3.,4.&5.) Primary Supply 22.5kV to 72.5kV 12 ft. (1., 3.) 4 ft. (2.,3.& 4.) Conductors Notes: 1. GO 95 Appendix E, Guidelines to Rule 35, Case 14, High Fire Threats 2. GO 95 Rule 35, Vegetation Management; Table 1, Case 14, High Fire Threats 3. CPUC Fire Threat Map: The CPUC has identified the District’s service territory as a Tier 2 High Fire Threat District (HFTD), with the Tahoe Donner Subdivision identified as a Tier 3, HFTD. Therefore, greater clearance requirements apply as compared to being in a non-fire threat area. 4. California PRC Section 4293 6 5. The minimum clearance may be reduced to 6 inches for tree trunks and major limbs “of sufficient strength and rigidity to prevent the trunk or limb from encroaching upon the 6 inch minimum clearance under reasonable foreseeable wind and weather conditions”; GO 95 Rule 35, Tree Trimming, Exception No. 4. Program Personnel District crews consisting of licensed Journeymen Linemen perform tree trimming operations on an as-needed basis. The majority of the Program work is performed by licensed tree contractors specializing in vegetation management operations for electric utiltities. The District has very strict requirements for selecting a tree contractor following the public procurement process. The contractor's field supervisor must be a certified arborist with the International Society of Arboriculture. The Contractor must employ only qualified line clearance tree trimmer personnel meeting the requirements of OSHA 29 CFR 1910.269, ANSI Standard Z133.1, and California Code of Regulation Title 8 Article 38 standards and requirements. In addition, the contractor must have a category D-49 Tree Service Contractor license issued by the California Contractors State License Board. Program Operation Elements 1. General Vegetation management operations are performed by mechanical trimming or removal of trees and other vegetation along distribution and transmission line circuits. These operations are performed in a manner which creates minimum damage to the natural vegetation and landscape not directly involved in the work. Ingress and egress to work areas are via existing roads, driveways, access roads, etc. The work is performed so as to cause the least possible obstruction and inconvenience to public traffic. Public vehicular and pedestrian traffic is allowed to travel through the work area with a minimum of interruption or impedance unless required by safety concerns. All traffic control and re lated devices conform to requirements set forth by the Town of Truckee. 2. Scheduled Maintaince Cycle Trees and vegetation are cleared from District facilities on a scheduled maintenance cycle program. The District's maintenance cycle goal is 5 years for all facilites. This means that trimming operations are performed on the same portion of a distribution or transmission line typically once every 5 years. The intent of the scheduled maintenance cycle program is to perform trimming necessary to obtain clearan ce that will last for the duration of the cycle. Other benefits include improved access to electric facilities and reduced future maintenance costs. Facilities are worked in a systematic approach. Operations are recorded by staff on the 7 District's Geographical Information Systems mapping database to track maintenance cycle goals. 3. Notificaion of Customers and/or Property Owners Customers and/or property owners are notified a minimum of twenty-four hours prior to any scheduled tree trimming operations adjacent to private property. The notificaion includes the type of work to be performed, including the trimming or removal of trees and the disposal of logs and/or brush. This is typically done by placing “door hangers” or using other communication methods to notify customers of impending work. The work may also require temporary power interrruptions or planned outages to be performed safely. The customer communication contains information such as contractor name, address, contact name, phone number, approximate time and duration of planned outage, etc. including District contact information. 4. Types of Trimming Natural pruning techniques are performed as recommended by the International Society of Arboriculture and ANSI Standard A300. Operations avoid practices that can cause damage or injury to the tree while achieving the required clearance objectives. Wherever possible, natural pruning cuts are made to direct future growth and sprouting away from electric facilities. a. Pruning: Tree pruning is performed so as to maintain the minimum clearance requirements from electric conductors as shown in the Clearances section of this document. Dead branches overhanging conductors are removed. Portions of dead or decaying trees or portions of trees weakened by decay or dis ease that may contact conductors from the side or by falling are pruned to eliminate the hazard. b. Crown Reduction: Trees directly under conductors are pruned and shaped. The tree crown is typically reduced and rounded into a symmetrical appearance as much as possible. Conifers are pruned in a natural manner that allows them to retain as much of their natural shape as possible. c. Side Prunes: Where line clearance tree pruning adversely alters the shape of a tree, additional pruning is performed to give such trees a better shape and appearance. 5. Tree Removal Tree removal is performed for all trees that do not meet the clearance requirement from the tree trunk to energized conductors and also for hazard trees. Hazard trees are trees with the potential to fail and threaten the reliability of the District’s overhead electric facilities. Hazard trees may be located inside or outside of the District’s right-of-way or easement. Hazard trees may be dead, dying, diseased, damaged, leaning or otherwise structurally unsound trees that could fall into electric facilities. Tree removal includes the falling of the entire tree and the removal and disposal of trunks, limbs and branches. 8 6. Pole Clearing Pole clearing consists of removing all plant material including grasses or low-lying shrubs, for a distance of not less than 10 feet in all directions from the outer circumference of an electric utility pole, for firebreak purposes. Pole clearing operations, as required by California PRC Section 4292, are only performed around poles that contain switches, fuses, transformers, or other electric equipment. 7. Control of Material and Clean Up Tree branches and other vegetation less than 5 inches in diameter are chipped and removed from the work area. Wood larger than 5 inches in diameter is cut into lengths for safe lifting purposes. Wood larger than 5 inches in diameter is made available to District customers before removal by the contractor. Customers on whose property a tree or trees have been removed or who are adjacent to such work will have the first opportunity to use the wood collected from such trees before removal by the contractor. The work is performed in an environmentally responsible manner with regards to any and all material generated by the work. Upon completion of the work, the area is cleaned to a condition at least equal to that which existed prior to the commencement of the work End of Document