Optimizing utility vegetation management investment for reliability, outage management
Vegetation management programs are a core component of electric utility system reliability and outage management strategies. Indeed, vegetation management is one of the largest preventative maintenance expenditure accounts for many utilities across the United States. Today, many utilities are looking to improve their vegetation management program to yield better operational benefits and to optimize returns on their investments.
Hawaiian Electric Company (HECO) formed an Asset Management department in late 2008. This department then developed investment and management strategies for key asset categories by modeling the asset base and forecasting performance under different investment scenarios. While this approach worked very well for critical asset categories such as transformers, breakers and other infrastructure equipment, a different approach was needed for vegetation management. HECO sought to address multiple questions to optimize their investment in vegetation management:
> What are the optimal trim cycles for vegetation Management?
> How much investment should we make in Right-of-Way (ROW), roadside/backbone, and lateral trimming?
> How do we justify the expenditure to the regulatory bodies?
KEMA worked with HECO to develop a sophisticated model that analyzed historical data for vegetation management activities, rainfall amounts, costs, and reliability performance metrics. The statistical analysis showed a high correlation between variables such as rainfall, trim cycles and interruption frequency. These correlations could be used to develop hazard curves for the different trim types. The hazard curves were then used to generate “return on investment” (i.e., efficient frontier) curves for each type of trimming—”return” being measured in terms of improved outage performance. Finally, the curves were used to determine the optimal portfolio of trim cycles by type for various investment levels. HECO is currently using this analysis and the other asset management strategies in support of a rate case filing.
KEMA’s Tom Myers will present the paper “Optimizing Investments in Vegetation Management” during the Enterprise Information and Asset Management track on Thursday, Feb. 2, 2011. This presentation will discuss the details of HECO’s work, current status, and lessons-learned from their experience.
Learn more about KEMA’s participation in DistribuTECH 2011.