Aims and strategic objectives of the committee

Aging factors Technical Committee (TC) mainly focus on gathering knowledge on insulation aging and failure mechanisms, study and testing of insulation system aging of rotating machines, transformers, cables, insulators, and other HV equipment. Research of insulation material aging is also included. 

We help to develop IEEE standards for evaluating material and insulation life under various aging factors and for evaluating electrical insulation lifetime with statistics methods. We also provide leadership, information, and coordination through the organization of technical meetings, workshops, sessions, and publications.  

Current activities:

  1. The TC is proposing to develop a new IEEE standard “Guide for statistical processing of failure data of electrical insulation system”.  This is a DEIS Standard.  The activity is a good opportunity for academics and industry to work together to develop an IEEE Standard. If you are interested in joining a Working Group to develop the IEEE standard, please contact Hugh Zhu at hzhu@ieee.org or Gian Carlo Montanari at gmontanari@fsu.edu.
  2. The TC is preparing a paper “Experience on accelerated aging testing of stator coils under repetitive pulse voltages” for the Electrical Insulation Magazine in 2021. If you are interested in the topic, please contact Hugh Zhu at hzhu@ieee.org.
  3. Hugh Zhu chairs a Working Group to revise IEEE1553 Standard “Test and Acceptance Criteria for Voltage-Endurance Testing of Form-Wound Coils and Bars used in Hydroelectric Generators and Large Pumped Storage Motors”.  The standard is going to Ballot soon.
  4. IEEE PES Materials Subcommittee is revising IEEE 1043-1996 “Recommended Test Procedure for Performing Voltage-Endurance Testing of Form-Wound Coils and Bars”.  IEEE1043 is a DEIS Standard. Hugh Zhu is a member of the Working Group to revise IEEE1043. 

Recent Activities & Achievements  

A workshop of “Insulation Aging of High Voltage Equipment” was held in International Conference on the Properties and Applications of Dielectric Materials in Xian, China on May 20, 2018.  Hugh Zhu chaired the workshop and the several TC members made the presentations in the workshop which attracted more than 60 people. Four speakers talked about aging and/or aging tests of the insulation system of cables, transformers, insulators and rotating machines. 

  • Aging and reliability of underground power cables – Presented by Harry Orton, Canada

The presentation discussed how high cable quality leads to high reliability of cable service and covered the related topics of manufacture, installation, testing, maintenance, condition monitoring and operation.   It was pointed out that a reduced standard within any one of these factors can accelerate aging and reduce reliability, so due attention and understanding of all factors must be maintained throughout cable life to minimize aging, increase reliability and guarantee a long service life.

  • Transformer Insulation Ageing: will ageing related failure be an issue for industry? – Presented by Prof. Zhongdong Wang of University of Manchester, UK

Accurate prediction of transformer lifetime is an interesting topic and often a desire for power utilities’ asset management (AM); and this is particular true when AM is applied to the mature power network infrastructure after many years’ operation. Replacement based on a fixed lifetime is costly and undesirable but ageing models are scarce with insufficient evidence or verification. Ageing, degradation and failure are the three mechanisms we often wish to conducts statistics by CIGRE working groups. In this talk laboratory accelerated ageing and in service ageing processes were discussed, as well as the comparison of conventional and new condition indicating parameters. In view of well-developed transformer factory test standards, new and sensitive ageing indicative parameters, and comparative change of future load scenarios to conventional cyclic load, this talk stimulated the debate on how realistic an ageing related thermal failure can be and whether lifetime is predictable for a power transformer population. 

  • Study of insulator aging tests under abnormal conditions  – Presented by Dr. Jun Zhou and Dr. Yu Deng of China Electrical Power Research Institute.

The operation environment of composite insulators includes serious icing, extremely cold, high humidity, coastal and high altitude areas which may affect insulator ageing.  The insulator performance under the abnormal or even extreme climate conditions was evaluated.  The insulator samples showed the aging effect of UV.  An ageing test station with the highest altitude in the world has been run for several years. The comprehensive impact of salt fog, strong wind and high temperature on the insulator samples from the coastal areas was studied. In addition, alpine and cold areas were also taken into consideration.

Accelerated Ageing Test

A comparison of the test results of the field observation and accelerated ageing tests showed that they were not equivalent. For example, hydrophobicity after 5000h accelerated ageing test in a lab was tentatively declined and recovered after a period of time, while hydrophobicity cannot recover to a certain level in the field tests. We are now establishing a database, including FTIR, TG and other chemical analysis from the various manufacturers and operational environment, to study the relationship between the environmental factors and material property.

Natural Ageing Test

A High Altitude Test Station is located in altitude of 4,300m and has been tested once a year since 2011. The test station provided the excellent test data of natural ageing of silicone rubber and composite insulators. There were 9 types of composite insulators and 11 types of silicone rubber insulators from the both domestic and overseas manufacturers. The test data, including hardness, hydrophobicity, FTIR, and TG, were collected to generate a database for future research.

  • Accelerated aging tests of stator winding insulation of HV generators/motors –  Presented by Dr. Hugh Zhu, USA.

In order for rotating machine insulation to operate reliably with good long-term performance, the first step is to ensure that new stator coils/bars are manufactured to a high-quality level and meet the design specification and expected performance requirements before they are installed in a generator or motor. The presentation described how to use accelerated aging tests to evaluate the quality of new stator coils and bars in the industry.  The accelerated aging tests (voltage endurance test and thermal cycling test) and the relevant international standards were described. Diagnostic tests to evaluate the outcome of the accelerated aging tests were also presented. The presentation covered the test methods, test requirements, international standards, and condition assessment of coil/bar insulation following the accelerated aging tests.

The photos below were taken in the workshop.

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Committee membership and affiliations

No.Member NameMember Affiliation
1Andrea CavalliniUniversity of Bologna, Italy
2Zhongdong Wang University of Exeter, UK
3Antonios Tzimas Advanced Energy, UK
4Xuezhong LiuXian Jiaotong University, China
6Hon SuenBC Hydro, Canada
7Jun Zhou China Electrical Power Research Institute, China
8Hugh ZhuChair of TC, Consultant, USA

For further information, contact:

Dr. Hugh Zhu

E-mail: hzhu@ieee.org