Transmission Lines, Trees and Vegetation
NYSEG’s Electricity Delivery System>>
There are two parts of the electricity delivery system: transmission and distribution.
The distribution system consists of the lines that bring electricity to homes and businesses. It is typically lower voltage (4.8 to 12 kilovolts [kv] or in some cases, particularly in rural areas, 34.5 kv). Distribution poles and lines are visible along streets, highways and in backyards, or they may be underground. NYSEG has 32,881 miles of distribution lines. For information on our vegetation management for the distribution system, click here.
High-voltage transmission lines, on the other hand, move large amounts of power from the place it is produced to our local distribution system. Transmission lines generally operate at 34.5 kv and higher. NYSEG has nearly 4,480 miles of transmission lines. These wires are typically strung on tall steel or wooden structures.
NYSEG has rights of way along both distribution and transmission corridors. We work with landowners, municipalities and regulatory agencies on vegetation management plans to help ensure safe, reliable service.
Transmission Lines and Reliability>>
Trees falling on power lines or branches coming in contact with power lines cause many transmission outages nationwide, according to the North American Electric Reliability Corporation (NERC), a regulatory organization that enforces reliability standards. In fact, the August 2003 blackout that disrupted service to many portions of the Northeast was traced in part to tree limbs coming into contact with transmission lines in Ohio.
In addition to our routine transmission maintenance work, as a direct result of the
2003 blackout the New York State Public Service Commission (PSC) does not allow trees to be pruned when they have the capacity to grow close to, come in contact with or fall into a high-voltage transmission line. In those cases, utilities must remove the trees. It is the responsibility of utilities to ensure that trees do not endanger transmission lines.
Our Vegetation Management Policy>>
NYSEG has a six-year vegetation management-control cycle. We inspect the system annually, and make adjustments where necessary to keep transmission lines clear of any obstructions.
Typically, visual inspections are done using vehicles and helicopters. Aerial patrols of the transmission system give us a bird’s eye view of any vegetation encroaching on transmission rights of way. We also use high-tech infrared thermography inspections to locate any “hot spots” that may be a sign of equipment that is stressed and in danger of failure. Our goal in using this high tech equipment is to spot problems and then address them before they inconvenience customers.
We have an established minimum clearance around wires, structures, and rights of ways that vary depending on the situation. The distance around wires can be up to 26 feet and to the edge of the right of way.
We may also remove trees outside of the rights of way if they present a potential hazard to the transmission lines. These removals require permission that was granted in the original easement or secured from the landowner. Dead and decaying trees are more likely to cause problems during storms and high winds.
Cutting, Treating, Mowing >>
We use a variety of techniques in vegetation management.
Trees and vegetation that could adversely impact reliability are cut or treated with herbicides to prevent future growth. Sometimes mowers are used to clear away vegetation.
Vegetation that is cut is disposed of using several methods:
- Lop and Scatter – Vegetation is cut close to the ground and debris is scattered.
- Windrow – Vegetation is cut and piled away from structures.
- Chipping – In yards, vegetation is cut, chipped and removed.
- Off-Site Disposal – Vegetation is removed from the site, sometimes to another site on the right of way).
We also use various herbicides, applied by truck or individuals using back-pack sprayers. Herbicide use is minimized and used selectively to control undesirable species while retaining low-growing vegetation. With tree stumps, we selectively apply herbicide to the stump to prevent re-sprouting.
We avoid using herbicides within:
- The immediate vicinity of streams or water bodies.
- 100 feet of a potable supply.
- Any orchard, nursery or crop planting.
- Any site restricted by the herbicide label.
- Active pastures.
There may be options other than herbicides depending on land use agreements. NYSEG forestry staff stay current on vegetation management techniques and herbicides by attending workshops and seminars.
Maintaining the Right Vegetation >>
NYSEG is committed to environmental stewardship and sustainable business practices. We advocate for desirable trees and vegetation within the rights of way of the distribution system. There are many shrubs, low-growing trees, and other vegetation that are allowed within the boundaries so that areas remain green.
We advise customers to plan before you plant or build. Consult with your local arborist or garden shop for varieties of low growing trees and vegetation. Always consider the location of transmission and distribution lines when planting or doing construction work. You can also visit the Arbor Day Foundation Website for plant selection and planting tips.
For Your Safety>>
- During or after storms, never attempt to remove trees or debris when downed power lines may be entangled in the debris.
- Leave cutting and pruning of trees near power lines to professionals. A tree or limb that contacts a power line could be deadly.
- Remind children not to climb transmission structures.