Power Transformer Condition Monitoring and Diagnosis

https://www.theiet.org/resources/books/pow-en/images/ptdcov.jpgBook title: Power Transformer Condition Monitoring and Diagnosis

Editor: Ahmed Abu-Siada

Year: 2018

Format:Hardback

Product Code: PBPO1040

ISBN: 978-1-78561-254-1

Description

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.

Book contents

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).

Problemas resueltos de fundamentos de ingeniería eléctrica

 

Portada del libro Problemas resueltos de ingeniería eléctrica

http://www.paraninfo.es/catalogo/9788428337892/problemas-resueltos-de-ingenieria-electrica

En este libro se incluyen 100 problemas resueltos de ingeniería eléctrica. Su objetivo es servir de preparación para los exámenes de evaluación continua y exámenes finales de asignaturas relacionadas con la resolución de circuitos eléctricos. Son problemas que han sido tradicionalmente propuestos en exámenes de Teoría de circuitos  y de Fundamentos de ingeniería eléctrica.

Está dividido en cuatro partes fundamentales:

  • Corriente continua
  • Corriente alterna
  • Sistemas trifásicos
  • Transitorios de primer orden

La estructura de los ejercicios está pensada para que los estudiantes puedan medir su propio aprendizaje. En cada uno de ellos se puede conseguir el aprobado en un tiempo razonable y siempre se incluye una pregunta de mayor dificultad que permite distinguir quién ha desarrollado capacidades adicionales frente a los que simplemente han entendido los conceptos básicos. Asimismo, los ejercicios se ordenan por su grado dificultad y por los conceptos fundamentales que evalúan. Al comienzo de cada capítulo se encuentran cuestiones básicas que se deben poder resolver en un tiempo limitado de diez minutos y a continuación se encuentran problemas con varios apartados y con la puntuación que se asigna a cada uno de ellos.

El libro Problemas resueltos de fundamentos de ingeniería eléctrica está también disponible en:

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Antennas in Partial Discharge Sensing System

Robles G., Albarracín R., Vázquez J.L. (2015) Antennas in Partial Discharge Sensing System. In: Chen Z. (eds) Handbook of Antenna Technologies. Springer, Singapore

Received: 26 September 2014; Accepted: 23 June 2015; First Online: 22 August 2015

Publisher Name: Springer, Singapore

Online ISBN: 978-981-4560-75-7

DOI: https://doi.org/10.1007/978-981-4560-75-7_95-1

Chapter: http://link.springer.com/referenceworkentry/10.1007/978-981-4560-75-7_95-1

Published in the Handbook of Antenna Technologies: http://link.springer.com/referencework/10.1007/978-981-4560-75-7

Abstract

The exponential growing demand of electricity has stimulated the manufacture of electric equipment with high rated powers withstanding tens and hundreds of kilovolts. These devices have to be insulated to ensure a safe and reliable service while their size and cost are reduced. Unfortunately, insulations deteriorate over time by being in operation under load and exposed to harsh environments that can degrade their behavior and lead to unexpected equipment outages and failures. The continuous monitoring of these assets is paramount in the operation of electric power systems, and one of the most popular methods to evaluate the ageing is the detection of partial discharges. Partial discharges are ionization processes that take place in voids filled with gas or oil inside the insulation, in dielectric surfaces, and in the proximity of sharp metallic objects. The chemical and physical structure of the insulation is changed, and eventually weakened, by the continuous action of the discharges. Then, their apparition can be directly a signal of problems in the insulation, but they can also be the consequence of other degradation processes. Partial discharges can be measured with a wide range of detectors including inductive, capacitive, acoustic, and light sensors. Because partial discharges occur in extremely short times, well below 1 ns, the radiofrequency measurement of the phenomenon in the HF, VHF, and UHF bands is also part of the unconventional methods used for their detection. EM sensors or antennas have the ability of performing a complete study on the measurement of partial discharges. They can detect pulses, localize the partial discharge site, and, to some extent, classify the type of partial discharge online. However, one of the most important challenges when using antennas in the diagnostic of insulations is the difficulty of relating the RF emissions to the severity of the PD. Another determent in the wide application of antennas as partial discharge detectors is the sample rate needed to obtain information from the signals in the time and frequency domains. The chapter also explores the most common configurations of antennas used in the detection of partial discharges as well as how they are installed and used in different electrical machines.

Keywords

Partial discharges Ultrahigh-frequency detection techniques Electrical insulation diagnosis Sensors Instrumentation Electrical measurements Ultrahigh-frequency measurements Antenna parametrization Electrical maintenance