7:00-8:00 AM

Transformer Protection
Instructor: Wayne Hartmann

(Based on IEEE C37.91)

Transformers are subject to internal faults, the effects of external faults and abnormal operating conditions impressed by the power system events the transformer no control over but must cope with. False (nuisance) trips are costly as the transformer and load are disconnected. Inability to trip due to lack of sensitivity, lack of certain protections or deficiencies in protection application may cause severe damage to transformers, negatively impact power quality and upset stability. Achieving the ideal balance of secure and dependable protection involves use of an array of elements that protect the transformer from prolonged internal faults, excessive through faults, when challenged by power system faults and anomalies.

  • Why transformers fail
    • The cost of failures
  • IEEE C37.91, Guide for Power Transformer Protection
  • Common transformer, bus and breaker connections
  • Explore non-electrical protections
    • Buccholtz (63)
    • Sudden pressure (63)
      • Sudden pressure relay supervision schemes
    • Thermal (49)
  • Explore electrical protections
    • GIC events
    • Overcurrent based (50, 51, 50N, 51N, 46)
    • Through fault protection (TFM)
    • Overexcitation (24)
      • Generating plant causes
      • T&D system causes
    • Differential: high set (87HS), restrained (87T) and ground (87GD)
    • CT performance issues (saturation, remenance, X/R ratio)
      • Transformer protection challenges (phase shift, ratio difference, inrush, grounding)
      • Percentage differential characteristics
      • Restraints for inrush and Overexcitation
        • Adaptive restraint for security
  • Realization of settings
  • Tools to view relay operation
    • Commission examples

8:00-10:00 AM


10:00-10:15 AM

Transformer Protection (continued)

10:15 AM-Noon


Noon-1:00 PM

Transformer Protection (continued)

1:00-2:45 PM


2:45-3:00 PM


Two Options:


1. Transformer Protection Calculations & Settings -
Differential Elements

Instructor: Dr. Murty Yalla

Building on the base knowledge covered in Transformer Protection Fundamentals, calculations for protective elements are developed. Depending on the element, these calculations use nameplate data, system data or a combination of the two. Margin considerations are explored and impacts on element reliability are discussed, as well as element interdependencies with protection and control in the transformer zone, whether in generation, transmission or distribution.

3:00-5:30 PM

2. Transformer Protection Hands-on Testing Lab Breakout Session
(Register early as seats will be limited for Breakout Session!)

3:00-5:30 PM

Seminar information is subject to change. Check this website regularly to confirm seminar details. Beckwith Electric reserves the right to make changes in programs or speakers, and to cancel programs if enrollment criteria are not met. Beckwith Electric’s liability is limited to refund of registration fees.