A relatively simple, but critical, component of LUCELEC’s efforts at improving reliability of the electrical system is vegetation management or tree trimming. Trees making contact with energized power lines (especially those comprising bare conductor such as the 66kV lines) can be hazardous, can affect the quality of the supply, and can lead to interruptions. Keeping trees clear of power lines is, therefore, very important and LUCELEC has an extensive programme in place to do that.
In the past LUCELEC undertook its own inspections of the transmission and distribution system to determine where trees needed to be cut or trimmed and would outsource the cutting or trimming to one of its contractors as needed. A few years ago, in an effort to improve efficiency in the process, annual contracts were issued to contractors for specific zones across the island to maintain the clearance of trees from electrical lines based on guidelines provided.
To minimise adverse effects on the environment measures are being employed to limit the extent of tree cutting undertaken, particularly in areas prone to land movements. Where possible, trees are trimmed rather than cut. However, LUCELEC is mindful that trees can be blown over or even be catapulted onto power lines during a hurricane and for this reason, depending on how critical a particular section of the power system is, more tree cutting may be undertaken in the vicinity of that section of line than in other areas. For example the extent of tree cutting around LUCELEC’s transmission (66kV) network (which provides the supply for large geographic areas and the backbone of its 11kV distribution system) is greater than around the low voltage distribution system.
Where trees must be cut and there are concerns about erosion, LUCELEC will work with landowners to replace the cut trees with other trees that do not grow as tall and would not interfere with the power lines. In some situations LUCELEC may find that it is more prudent to redesign the distribution system, including making use of the more expensive ‘insulated’ 11kV overhead cable, to limit or avoid tree cutting totally.
Generally, LUCELEC will not cut trees in the vicinity of its service lines (that is the black insulated lines that run from the pole to a building). If a tree needs to be trimmed or cut in the vicinity of a service line because it may pose a threat to a house, LUCELEC will come in if a request is made to drop the service line temporarily to allow the landowner to cut or trim the tree in question.
Any property owner or member of the public who thinks that a tree poses a threat to power lines may call LUCELEC’s customer service desk, visit any one of the company’s offices, write a letter to the Managing Director or send an email to [email protected] to make a report. Upon receipt of such a report LUCELEC will visit the location to assess whether the tree poses a threat to power lines, property or life in order to take the necessary measures. Members of the public should not attempt to trim branches or cut trees that are in contact with power lines or when there is any possibility that the branch or tree may fall onto a power line, as this may result in an electric shock.
All requests received pertaining to tree trimming or cutting are generally investigated within two days and the requisite actions to remove high priority trees or branches are undertaken within three days thereafter. Generally, LUCELEC determines the priority to be given to tree trimming requests based on the proximity of the tree or tree branch to the lines and the health of the reported tree or branch.
Comments or questions about this article can be emailed to [email protected].