LiDAR and the Bulk Power System

In the last installment, I discussed the regulation of the bulk transmission system in North America, pointing out the roles of the Federal Energy Regulatory Commission (FERC) and the North American Electric Reliability Corporation (NERC). When you hear about regulatory practices, it will typically be referenced to NERC. In addition to NERC, there are a number of regional regulatory entities that roll up to NERC (for example, ISO New England). For our purposes, an understanding of the best practices recommendations by NERC and its enforcement authority are sufficient.

While LIDAR can play an important role in all overhead electrical wires, we are primarily interested in the bulk power system. Quoting NERC Bulk power system means facilities and control systems necessary for operating an interconnected electric energy supply and transmission network (or any portion thereof), and electric energy from generating facilities needed to maintain transmission system reliability. The term does not include facilities used in the local distribution of electric energy. Prior to the end of 2010, the definition for the regulatory compliance areas in which we are interested was limited to transmission lines of 200,000 (200 kV) and above. A significant (to the LIDAR industry) change was finalized in November of 2010 that reduced this to 100 kV (FERC Docket RM09-18-000, finalized by FERC Order No. 693, 18 Nov 2010). This expanded the bulk transmission lines in North America of 100 kV and above to over 450,000 miles!

There are two primary areas of interest in bulk transmission to LIDAR operators. Both of these areas are under the NERC Facilities Design, Connections and Maintenance (FAC) category and hence you will see informational and regulatory documents referred to as FAC-xxx notices. You can find all of the NERC documents at under Standards.

The first area is line rating, governed by FAC-008. Line rating refers to the amount of energy a given transmission line can carry under a given set of environmental conditions (for example, rated load decreases with increasing ambient temperature). Under NERC FAC-008, transmission operators are required to rate and report on their bulk transmission lines (the reporting requirements are actually under FAC-009, Establish and Communicate Facility Ratings). Methods could vary widely, including models based on engineering build-to specifications. On October 7, 2010 NERC issued an Alert entitled Recommendation to the Industry: Consideration of Actual Field Conditions in Determination of Facility Ratings. Under this alert, NERC effectively directed the transmission operators to develop ratings based on actual field conditions. Operators were to report on the methods they would employ to achieve true field condition models by 15 December 2010 and to report any deviations between design and field by 7 April 2011! When this Alert was issued, I heard many LIDAR operators exclaiming that NERC was now requiring LIDAR for transmission line rating. This is not quite correct. In the background section of the Alert, NERC cites what it considered to be a successful rerating exercise which employed airborne LIDAR and modeling using Power Line Systems PLS-CADD. Thus while not specifically required, there is a strong hint that NERC will be receptive to plans that employ LIDAR for rating.

The second major area of interest for LIDAR providers is Transmission Line Vegetation Management. The NERC area for this is FAC-003 (see NERC FAC-003-2 Transmission Vegetation Management Standard Technical Reference). Here the job is to monitor transmission line-vegetation clearance and take corrective action in a proactive program to prevent line-vegetation arcs and subsequent cascade system failures. The required modeling includes both static and wind sway of wires.

Now obviously these two are related in that both data sets can be derived from the same LIDAR mission. The vegetation monitoring requires a physical inspection of the transmission line on an annual basis. This implies that approximately 450,000 miles of bulk transmission lines must be modeled on an annual basis! If we estimate $1,500 per mile (your mileage may vary!) for data collection and modeling (including line rating), this amounts to $675 million per annum! As you can no doubt imagine, the bulk transmission operators are seeking a compromise with NERC and approaches for lower cost.