Editor: Ahmed Abu-Siada
Product Code: PBPO1040
Power transformers are a key asset for electricity utilities around the globe. However, aging populations of large power transformers require reliable monitoring and diagnostics techniques to extend the asset’s lifetime and minimise the possibility of catastrophic failure. This book describes the most popular power transformer condition monitoring techniques from principles to practice.
Topics covered include concepts and challenges in power transformer condition monitoring and diagnosis; dissolved gas analysis, measurements and interpretations; moisture analysis for power transformers; assessing degree of polymerisation value considering thermal ageing and paper moisture; frequency response analysis; monitoring of power transformers by mechanical oscillations; lifecycle management of power transformers in a new energy era; and other topics in power transformer asset management and remnant life. Each chapter covers the fundamentals and theory of the topic, and conveys techniques to measure relevant parameters and assess or interpret the results.
Chapter 1: Dissolved Gas Analysis, Measurements and Interpretations- Carlos Gamez
Chapter 2: Power Transformer Condition Monitoring and Diagnosis: Concepts and Challeges- Ricardo Albarracin, Guillermo Robles, Jorge Alfredo Ardila-Rey, Andrea Cavallini, Renzo Passaglia
Chapter 3: Moisture Analysis for Power Transformers- Belen Garcia, Alexander Cespedes, Diego Garcia
Chapter 4: Assessing DP Value of a Power Transformer Considering Thermal Ageing and Paper Moisture- Ricardo David Medina et al
Chapter 5: Frequency Response Analysis- Mehdi Bagheri, Toan Phung
Chapter 6: Monitoring of Power Transformers by Mechanical Oscillations- Michael Beltle
Chapter 7: Lifecycle Management of Power Transformers in a New Energy Era- Carlos Gamez
Chapter 8: Power Transformer Asset Management and Remnant Life- Norazhar Abu Bakar
Chapter 2: Partial discharges: keys for condition monitoring and diagnosis of power transformers
The combination of thermal and electrical stress, in conjunction with the synergic effects of moisture in the insulation, might dramatically reduce the lifetime of a power transformer, which is roughly estimated to be 40 years if properly maintained, meaning that many transformers do not experience any failures before being dismantled. Mechanical stresses during short-circuits can also play a role leading, in the worst case, to the radial buckling of the winding and damage of the connection cables at the bushing terminations. A number of these factors can, in the course of time, give rise to partial discharge (PD) phenomena which can be a cause of failure or a symptom of degradation. PD measurements can be carried out conventionally, following the standards IEC 60270 and IEC 60076. Alternative methods, such as those presented in the IEC TS 62478 standard based on acoustic or ultra-high frequency sensors, have been proposed and might offer better sensitivity, particularly for monitoring purposes, and the capability to locate the PD sources. For all these methods, identification of the PD source is a key to achieve a correct course of action (run, repair and replace).