Vegetation Management Grow-In Data
Leading Indicator: Vegetation Management


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About this Leading Indicator

Conductor contact with trees has been an initiating trigger and a contributing factor in several major system disturbances since 1965, including the blackout of August 14, 2003. Tree contact caused the loss of multiple transmission circuits in several of the outages, causing multiple contingencies and further weakening of the system. By carefully tracking and enforcing standards related to inadequate vegetation management, we are able to identify and eliminate the causes, with the goal of preventing line outages from vegetation located on transmission rights-of-way (ROW) and minimizing outages from vegetation located adjacent to ROW.

NERC began collecting vegetation-related outage information in 2004 as a result of the August 14, 2003 Blackout. NERC continues to aggressively pursue the reduction of vegetation-related transmission outages through compliance and enforcement programs that launched on June 18, 2007.

NERC continues to broaden its effort to reach at-risk registered entities. Targeted initiatives include quarterly vegetation management reports (available here) along with detailed outage and compliance information. In 2007, NERC and the Regional Entities conducted over eighty compliance audits, focusing on each requirement of NERC standard FAC-003-1. Compliance monitoring also includes periodic (monthly/quarterly) data reporting and self certification of vegetation-related outages by transmission owners.