Abstract:
This session introduces the principals of magnetic flux, electromagnetic induction, self-inductance and mutual coupling and gradually uses these concepts to explain the behavior of a power transformer. Included is a discussion and explanation of leakage flux, leakage impedance, magnetizing reactance, load losses, no load losses and inrush current. The classical steady state transformer model is gradually constructed as the course progresses. If time permits the per unit system will be introduced and, using that, an actual two winding transformer test report will be examined and numerical values will be derived for the associated transformer model. If time further permits, a three winding transformer test report will similarly be boiled down to create the associated model. Although the presentation is not devoid of mathematical derivations, it's objective is primarily to give the student a seat of the pants understanding of the various concepts introduced. Also the focus will primarily be on single phase transformers with occasional exceptions during the introduction of the per unit system, 3 phase transformer test report analysis and an explanation of phantom tertiaries.

Bio:
Mr. Cirka received a BS-EE in 1973 from WPI and a ME-EPE (electric power engineering) in 1982 from RPI. He is a Principal Engineer - System Protection Engineering at National Grid. He has a total of 35 years of utility power engineering experience primarily in system protection and control but also including distribution engineering and generation engineering with National Grid, it's predecessor New England Electric System, PSNH and Northeast Utilities. He is a registered PE in the State of New Hampshire.

Abstract:
This session will consider the various aspects of transformer protection including overcurrent protection, voltage and surge protection, and auxiliary and supplemental protection and monitoring. We will review the ANSI standards regarding transformer loading, protection, and development of the transformer damage curve. We will examine considerations for protection from overloads and from both internal and external short circuit conditions. We will briefly look at the requirements for and application of surge protection on medium and high voltage transformers. Finally, we will discuss various types of supplemental monitoring and protection systems including sudden pressure and Buchholz relays and on-line moisture and gas-in-oil monitoring systems.

Bio:
Mr. Secrest has over 25 years of experience in the design, installation, and commissioning of low, medium, and high voltage electric power distribution and generation plants. He is currently Director of Engineering for Three-C Electrical Company, Inc. where he oversees the in-house engineering staff as well Three-C’s field relay engineers and technicians. He has served in engineering design and management positions for Greenman-Pederson, Inc, Sage Engineering Services Company, R. W. Beck, and McGraw-Edison. Mr. Secrest holds Bachelor of Science and Master’s of Engineering degrees in Electric Power Engineering from Rensselaer Polytechnic Institute, is a member of the IEEE PES and IAS, and is a licensed professional engineer in seven states.

Abstract:
This will be a comprehensive session focusing on diagnostic testing applications for power transformer assets. Attendees will gain a better understanding of the diagnostic testing practices and requirements. All aspects of electrical field testing will be covered, including proper test protocol, application techniques, and data analysis strategies. Both standard and newly emerging advanced techniques will be presented. The session will investigate on how to collectively use the test results to best determine the overall condition of the power transformer under test. All subjects presented are adequate for all levels of expertise.

Bio:
Charles Sweetser received a B.S. Electrical Engineering in 1992 and a M.S. Electrical Engineering in 1996 from the University of Maine. He joined OMICRON electronics Corp USA, in 2009, where he presently holds the position of Technical Service Manager for North and South America. Prior to joining OMICRON, he worked 13 years in the electrical apparatus diagnostic and consulting business. He has published several technical papers for IEEE and other industry forums. As a member of IEEE Power & Energy Society (PES) for 14 years, he actively participates in the IEEE Transformers Committee, and presently holds the position of Chair of the FRA Working Group PC57.149. He is also a member of several other working groups and subcommittees.

Abstract:
The insulation system is a critical component of a power transformer, composed of both solid and liquid. In this presentation Mr. Prevost will review the basic functions which the insulation system must perform in a power transformer. Manufacturing practices will be reviewed which if followed will maximize the integrity of the insulation system over the life of the transformer. Insulation aging mechanisms will be reviewed so that they can be incorporated into operation and maintenance practices in order to maximize transformer life. New and alternative insulation materials, both solid and liquid, will be reviewed as well.

One use of the insulating fluid in a power transformer is to transfer information about the integrity of the transformer by means of diagnostic testing of the fluid. Diagnostic tests such as Dissolved Gas Analysis (DGA) which can predict faults within the transformer will be reviewed. Oil quality tests such as moisture content, dielectric strength, interfacial tension, acid number, and dissipation factor which can further contribute to the diagnostic interpretation of the transformer condition will be reviewed as well. The interpretation of Furans in the insulating fluid to predict transformer insulation life will also be discussed.

Bio:
Thomas A. Prevost is the Vice President Technology at Weidmann Diagnostic Solutions Inc. He has been employed with Weidmann Electrical Technology since 1985. He joined the Weidmann Diagnostic Solutions team in September 2006. Previously he was the Vice President of Technical Service at EHV-Weidmann, a manufacturer of electrical insulation materials for the transformer industry. Prior to that he worked at Tampa Electric Company as an engineer in distribution and production. Thomas received his BSEE from Virginia Polytechnic Institute.

Thomas is a senior member of IEEE. He is a Past-Chair of the IEEE PES Transformers Committee. He is a member of the IEEE Standards Association-Standards Board where he serves as Chair of the New Standards Committee (Nescom). He is also a member of the IEEE PES Board of Governors. Thomas is also active in ASTM committee D27 on Insulating Fluids and IEC committee TC 10 on Insulating Fluids.

He has written many technical papers on the subject of electrical insulation materials and transformer diagnostics.

• Common Transformer Configurations
• Autotransformer
• 2-winding
• 3-winding
• Zig-zag winding
• Phase shifter
• Grounding transformer
• Shunt reactor
• Mobile transformer
• De-energized tap changers
• Load tap changers
• Common Transformer Cooling Configurations & Thermal Modeling
• ONAN
• ONAF
• OFAF
• ODAF
• IEEE loading guide thermal model
• Operation Beyond Nameplate Rating
• Electrical implications
• Thermal implications
• Tap winding ratings
• Interpreting Transformer Alarms
• Determining transformer state from alarm & gauge indications
• Recommended action decision based on
• Apparent problem level
• Available reaction time
• Condition information
• Dynamic Rating
• Operation based on
• Transformer condition
• Transformer state
• Ambient conditions

Bio:
Wayne holds a B.S. Degree in Electrical Engineering from Lafayette College and an M.S. Degree in Electrical Engineering and Computer Science from the Massachusetts Institute of Technology. He was a research engineer at MIT for 21 years, performing electromagnetic apparatus research in areas such as modeling and on-line state/condition estimation and monitoring of motor-operated valves and large power transformers, advanced turbine generator concepts, and development/implementation of sensors and intelligent software systems for condition monitoring. Since 2002, Wayne has been a lead engineer in substation engineering for NSTAR Electric with responsibilities including vendor technical interface, new substation equipment commissioning, mobile transformers, and condition assessment and maintenance/replacement planning for large power transformers. He has been a member of IEEE since 1976 and co-holds a patent for “Apparatus and Method for Non-Invasive Diagnosis and Control of Motor-Operated Valve Condition.”