IEEE Transformer Committee Report

Scott Reed, MVASpecifications & Standards, Spring 2022 Specifications & Standards

With the global pandemic continuing, the IEEE Transformer Committee was forced to conduct the fall meeting virtually. Despite the inability to meet together, the IEEE Transformer Committee remains very active and is committed to developing stronger guides to help the power industry. 


Within the Insulating Fluids Subcommittee, the working group for C57.146, IEEE Guide for Interpretation of Gasses Generated in Silicone-Immersed Transformers continues to analyze DGA data for silicone-filled transformers. Although the installation of new silicone-filled transformers is not as common as when the guide was developed, many silicone-filled transformers remain in service, so there is a value to the data for the users. The working group has found a variance to the limits originally established, so ideally, the goal is to establish a 90th and 95th percentile DGA status for each gas, similarly to how C57.104, IEEE Guide for the Interpretation of Gases Generated in Oil-Immersed Transformers was modified.


A new working group was established for C57.637, which as currently written is only for the reclamation and reconditioning of mineral oil-filled transformers. While work has just begun, the goal is to expand this guide to include the reclamation and reconditioning of other fluids — natural esters, synthetic esters, less-flammable hydrocarbons, and silicone fluids. If the guide is approved, the new title will be IEEE Guide for Reclamation and Reconditioning of Insulating Liquids. It will be a much more useful guide for users in the utility and the service industries, which has many industrial clients that utilize these fluids in transformers.     


Similarly, a new task force was established for the interpretation of DGA date in liquid-filled load tap changers. Again, with the introduction of alternate fluids in the power industry, the goal of this guide is to expand this guide beyond mineral oil. The gas generation and ratio analysis is a function of the fluid type, so each type of fluid gassing must be analyzed individually. As a result, the revised C57.139 guide, if passed, will be called the IEEE Guide for Interpretation of Gases Generated in Liquid-Type Load Tap Changers.


Finally, C57.155, IEEE Guide for Interpretation of Gases Generated in Natural and Synthetic Ester has also formed a new working group. The goal of this working group is to refine the diagnostic tool of the guide by analyzing historical DGA test results for transformers filled with natural esters and synthetic esters so that the 90th and 95th percentile limits can be established.


Within the Performance Characteristics Subcommittee, C57.149, IEEE Guide for the Application and Interpretation of Frequency Response Analysis for Oil-Immersed Transformers continues its work on revising and improving the guide. Transformer connection tables are completed, and the working group is looking to add case studies to help the user better understand what to expect when issues such as radial displacement, axial displacement, short-circuit failures, or transportation issues occur.


Within the Standards Subcommittee, the working group for C57.152, IEEE Guide for Diagnostic Field Testing of Fluid-Filled Power Transformers, Regulators, and Reactors continues to update the guide. The purpose of this guide is to provide users with a document on what electrical testing should be performed throughout the life of a transformer and when. It is expected that there will be changes to the bushing testing section of the guide. The current guide expires in 2023, and work is progressing to meet the deadline.


Within the Power Transformer Subcommittee, C57.143, IEEE Guide for Application for Monitoring Equipment to Liquid-Immersed Transformers and Components received an extension to revise the guide. It is expected to go to ballot in spring 2022, with significant changes to the guide for on-line moisture and bushing monitoring.


Elsewhere in the Power Transformer Subcommittee, C57.93a, IEEE Guide for The Installation and Maintenance of Liquid-Filled Power Transformers has developed a cold start-up testing procedure to test liquid-filled power transformers filled with natural ester and cooled to -40°C. The purpose is to study the effects of energizing a transformer when the fluid, with such a high pour point, is solidified. The goal is to learn from this experiment in an effort to establish a cold startup procedure.


Finally, in the Power Subcommittee, a new working group was formed that will focus on phase shift transformers.


Within the Insulation Life Subcommittee, work is almost completed for C57.162, which is the new guide for moisture in insulation. It is expected to go out to ballot in spring 2022 and will also include discussion on bubble evolution. Bubble evolution is a phenomenon that occurs when a transformer with wet insulation is overloaded, causing water to be released from the paper.


Within the Dielectric Tests Subcommittee, work continues on resolving the draft comments for C57.160, IEEE Guide for the Electrical Measurement of PD in HV Bushing Instrument Transformers.

Scott Reed is President of MVA, a NETA Corporate Alliance Partner that specializes in the oil diagnostic analysis and vacuum filling and oil processing of substation transformers throughout the United States. He received a BS in electrical engineering from North Carolina State University with a concentration in power. He performed relay system protection design work at Baltimore Gas & Electric and worked servicing transformers for 30 years before starting MVA. Scott has written and published various papers for the industry and is very active with the IEEE Transformer Committee where he serves as Chairman of the IEEE Subcommittee of Insulating Fluids; Vice Chairman of IEEE Std. C57.166, Acceptance and Maintenance of Insulating Liquids in Transformers; and Secretary of IEEE Std. C57.93, Installation and Maintenance of Liquid Immersed Power Transformers. He can be reached at or 330-498-6259.