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eng Effective bushing diagnosis using partial discharge testing
Badicu, Laurentiu Viorel; Koltunowicz, Wojciech; Subocz, Jan
Transformers Magazine Vol. 4, No. 4, 2017
This article demonstrates how the inclusion of partial discharge as a measurement parameter ensures a more reliable diagnosis of insulation condition in transformer bushings. Comparative diagnostic tests showed that the partial discharge measurements best enabled the detection of bushing defects, which the other methods were not able to detect alone. The tests were performed in the lab on oil-impregnated paper (110 kV – with induced defects) and resin-bonded paper (52 kV – with design flaws) bushings. The bushings were subjected to long-term AC...
Hrčak ID: 194840


eng Super large capacity converter transformer
Zhou, Yuanxiang; Huang, Xin
Transformers Magazine Vol. 8, No. 1, 2021
Nowadays, the huge demand for long-distance UHVDC transportation prompts research on the super large capacity converter transformer. Especially in China, UHVDC projects are widely built and put into use. This article reviews the history of converter transformer research and introduces details in the design of the converter transformer. The recent advances in the fundamental study of converter transformers such as partial discharge, space charge, and material performance test are also introduced in the article. In the end, this article summarize...
Hrčak ID: 249885


eng On-site partial discharge diagnostics of cast-resin transformers
Engelen, Christoph; Krüger, Michael; Ranninger, Udo; Kraetge, Dr. Alexander
Transformers Magazine Vol. 8, No. SE2, 2021
The amount of installed cast-resin dry-type transformers has been increasing steadily over the past years due to its wide application range in industrial areas and in the renewable energy sector [1][2]. The lack of mineral oil as an insulating medium allows dry-type transformers to be used in areas with high fire hazards and environmental protection requirements such as in tunnels, buildings or wind power plants. Therefore, rendering these units more and more important in the electrical grid. However, some well-established diagnostic methods,...
Hrčak ID: 267206


eng Advanced transformer condition assessment – Part II
Giesecke, Jon L.
Transformers Magazine Vol. 3, No. 4, 2016
Infrared Thermography, Ultrasonic Noise Analysis, Partial Discharge Detection, Dissolved Gas Analysis, Vibration Analysis – all these techniques are great stand-alone diagnostic tools; however, when used properly, combining the data obtained through each technique, an incipient fault can be identified long before it degrades the insulation and creates a failure. This paper will provide guidance in setting up a complete Predictive Maintenance program to be able to provide owners of oil-filled power transformers (4 kV and up), i.e. utilities, re...
Hrčak ID: 167112


eng Advanced transformer condition assessment – Part I
Giesecke, Jon L.
Transformers Magazine Vol. 3, No. 3, 2016
Infrared Thermography, Ultrasonic Noise Analysis, Partial Discharge Detection, Dissolved Gas Analysis, Vibration Analysis – all these techniques are great stand-alone diagnostic tools; however, when used properly, combining the data obtained through each technique, an incipient fault can be identified long before it degrades the insulation and creates a failure. This paper will provide guidance in setting up a complete Predictive Maintenance program to be able to provide owners of oil-filled power transformers (4 kV and up), i.e. utilities, re...
Hrčak ID: 167399


eng Medium and Low Voltage Cable Measurements - TD, PD, LIRA
Čeović, Josip; Širola, Matko
Journal of Energy Vol. 65, No. 1-2, 2016
Elmont d.o.o. Krško – We have spread our main scope of the services from electrical maintenance, modifications implementations and quality control to cable testing area. The main reason for expanding our scope was to support Nuclear Power Plant Krško Cable Aging Management program and the world trend of LTE (Life Time Extension) in power plants. Scope of work – We are identifying potential downgraded conditions for safety and operational important cables in special areas (heat, water, radiation). Our main scope is visual control, and testi...
Hrčak ID: 199623


eng Diagnostic testing of cast-resin transformers
Kruger, Michael; Engelen, Christoph
Transformers Magazine Vol. 5, No. 2, 2018
Cast-resin power transformers are widely used in areas of high standards concerning fire hazards and environmental protection. The most common reason for failures of cast-resin transformers is the electric breakdown of the cast-resin insulation between turns or parts of the windings. In many cases, partial discharges (PD) occur before the breakdown happens. By testing the windings with induced voltage in combination with a sensitive PD measurement, the risk of unforeseen outages can be minimized. Methods for performing the induced voltage test...
Hrčak ID: 198839


eng Acoustic localisation of partial discharge in power transformers
Hoek, Stefan; Ranninger, Udo
Transformers Magazine Vol. 2, No. 4, 2015
Detecting partial discharges in the insulation system of a power transformer at an early stage reduces the risk of total breakdown. One method to detect partial discharges is acoustic measurement. With this technique detection and localisation of partial discharge is possible by placing acoustic sensors on the surface of the transformer tank. The low impact of electrical interferences from outside the measurement set-up constitutes one of the strengths of the acoustic method. A further advantage is the ability to identify the position of the pa...
Hrčak ID: 182323


eng Trends in continuous on-line condition monitoring
Coenen, Sebastian
Transformers Magazine Vol. 2, No. 3, 2015
The article describes new trends in the field of continuous on-line condition monitoring of transformers. These trends are related to the following topics: the monitoring system itself and new requirements for, for instance, HVDC and offshore transformers; growing importance of the implementation of continuous on-line monitoring of bushings, dissolved gases and new ultra-high frequency technology for partial discharge monitoring; and finally, the new trend of using IEC 61850 [1] data model and communication protocol in digital substations.
Hrčak ID: 182742


eng Condition assessment of transformer insulation during routine partial discharge (PD) tests and in-service monitoring
Gorgan, Bogdan; Koltunowicz, Wojciech; Zander, Patrick
Transformers Magazine Vol. 9, No. 4, 2022
To compare the results of in-service PD measurements with the results of conventional measurements previously performed during transformer routine testing in the factory, the use of alternative PD methods in the factory is proposed. The effective comparison of PD data results is possible with a measuring system with advanced hardware and software features. The minimum requirements of such a versatile PD measurement system are presented, and an example of the comparative measurements with conventional and alternative methods performed on a 1.6 M...
Hrčak ID: 285178