Asset priorities based upon business values
Hydro One has identified 63 distinct classes of assets that make up its transmission and distribution systems. They range from cables, transformers and switches to buildings and rights-of-way. These 63 classes were prioritized in three groups in accordance with their value to the business. The first and second (high value) groups were reviewed exhaustively, recognizing that failure could have a severe impact on business values, and that associated investment and maintenance programs for these groups involve significant annual expenditures. The third (lower value) group was reviewed in general terms, since the expenditures and impact on business values are relatively minor.
Best practices and process review
For each of the high value categories, Acres carried out an exhaustive review of condition assessment practices and asset data. This included a description of the asset class, the population demographics of the asset class within the Hydro One system, assessment of industry best practices for maintaining and testing that class of assets, a review of asset deterioration processes and failure modes, development of criteria for measuring the condition of the assets, and criteria for identification of "end-of-life" for that class of assets. When gaps were identified in the Hydro One maintenance and testing program compared with industry best practice, recommendations were made for additional testing to correct the deficiencies. Finally, audits were undertaken to ascertain the quality of the condition data collected by Hydro One.
Development of Health Indices and condition results
Based on the recommended criteria, and the adopted base of condition data, the condition of each class of assets was summarized in the form of "Health Indices" (HI). These HIs are based on the industry's best practices and on known effects of deterioration factors and their contribution to end-of-life for each asset group. Hydro One's data was applied to the HIs and the results categorized in five condition groups from "Very Poor" to "Very Good" on a scale of 0 to 100. Interpretation of HI results has to take into account the nature of the asset being rated; for example, end-of-life has a different meaning for a transmission right-of-way than for an air-blast circuit breaker.
A typical set of Health Index results for a single Asset Class
Condition based asset management - a basis for decision making
Upon completion of reviews for all 63 assets, a final report was submitted to Hydro One that will form an important information source for investment and maintenance programming decisions within Hydro One. Acres will provide assistance in this process, primarily in the interpretation and utilization of the asset condition data. Acres will also defend the audit and the resulting asset condition evaluations at future regulatory hearings.
Invention of a new "niche" for Acres and Hydro One
Through this project a vast amount of knowledge and expertise has been acquired by both Acres and Hydro One. The concepts, algorithms and practicalities of the "Composite Health Index" have been developed and implemented for most asset groups within transmission and distribution systems. The methods applied are truly inventive, and consequently Acres and Hydro One have theorized this further and submitted a paper to the IEEE on the subject. It is clear that Acres is now amongst industry leaders, from a theoretical to a practical perspective, in assessing the condition of T&D assets. Similarly Hydro One is a worldwide leader of utilities in applying state-of the art techniques for the condition info-support of its asset management decision models.
For further information please contact:
Myles Godfrey, Project Manager, Asset Management
Acres International, Oakville, ON
905-469-3400
mgodfrey@acres.com
Thorhallur Hjartarson, Team Leader, Asset Management
Acres International, Oakville, ON
905-469-3400
thjartarson@acres.com