This piece was originally published in the July 2018 issue of electroindustry.
William Mao, Global Product Marketing Manager for Power Transformers, ABB
Mr. Mao has held various sales and management positions in the electroindustry.
The United States Congress, the U.S. Department of Energy, and many public utilities have stated in recent years that it is critical for the country to create a national spare transformer program in order to ensure greater grid reliability and resilience in case of superstorms, physical attacks on the grid, and other catastrophic events. It is essential to have spare transformers on hand because the lead time for a single replacement can be as long as 18 months.
Such a spare transformer program, like the one recently announced by Grid Assurance LLC, would cover critical bulk transmission assets such as transformers—typically rated 200 MVA or greater—used in transmission system interconnections that tie power generation and load centers across the country. The DOE’s 2017 Strategic Transformer Reserve Report called for an industry-led solution.
Grid Assurance was the first LLC to proceed, collectively having subscribers with transmission facilities in 26 of the continental 48 states, consisting of 31 transmission subsidiaries of AEP, Berkshire Hathaway Energy’s MidAmerican and NV Energy, Eversource, FirstEnergy, Kansas City P&L, and National Grid. Other subscribers may join in the future. Grid Assurance operates via a subscription business model where participating utilities have immediate access to these spares following any qualifying event.
Through thorough analysis of catastrophic event impacts, combined with identifying common large power transformer spare requirements for ratings of 230 kV and above, Grid Assurance, with support from ABB and other companies, is helping American utilities shape the first strategic national transformer spare program.
Once the inventory is established, a strategic reserve must also employ cost-effective, practical maintenance and storage plans. These needs can be addressed by leveraging a digital platform and condition-based analysis.
The unique challenge of a spare program dedicated to high-impact, low-frequency events is how to store transformers that may not be placed into service for several years but still need to be ready for rapid deployment on demand. Warehousing recommendations factoring in important spare parts (including electrical bushings and cooling equipment) are important to consider, as well as geographic differences in terms of seismic, climate, and accessibility conditions.
Grid Assurance, and other programs that may develop worldwide, would potentially require hundreds of transformers to be manufactured in addition to those transformers required for normal grid upgrade purposes. From the beginning, ABB has played a leading role in creating an industry collaboration to create and build upon a strategic national spare transformer program that is essential to ensuring a stronger, more resilient transmission grid for the future.