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eng RIF® bushings: The paperless, dry-type bushing technology
Euvrard, Eric; Middleton, Robert L.
Transformers Magazine Vol. 4, No. 5, 2017
Paper-insulated bushings (OIP and RIP) have been the dominant bushing type for the power transformer industry for many years. However, as our transformer assets age, bushing failures can become more frequent. Resin-impregnated fibre bushings offer the user a paperless and dry-type alternative for MV, HV and EHV condenser transformer bushings. Two technologies are currently offered: resin-impregnated fiberglass (a proprietary technology trademarked RIF®) and resin-impregnated synthetic (RIS). This article will discuss the RIF® bushing technology...
Hrčak ID: 202523


eng Retrofitting of 245 kV OIP bushing with longer oil-end
Murty, K.K.; Kapil, J. J.; Dubey, Santosh
Transformers Magazine Vol. 6, No. 4, 2019
This article focuses on an original case-history of replacement of a leaky 245 kV OIP bushing of a 220/132/33 kV, 160 MVA, transformer on site at the 220 kV Jabalpur substation, in Madhya Pradesh state in India with an available 245 kV OIP bushing having longer L-2, Fig. 1. To retrofit the same turret-adopter, an extension piece was fabricated, with an innovative idea of utilizing locally available materials and in-house resources in minimum downtime on site, without re-locating or dismantling the transformer, thus giving the transmission and...
Hrčak ID: 226064


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 Condenser bushings condition monitoring
Murty, K.K.
Transformers Magazine Vol. 4, No. 5, 2017
This article focuses on condenser bushings monitoring, of both oil-impregnated and resin-impregnated paper bushings, for extra high-voltage class transformers in order to avoid a catastrophic transformer failure that might result from a failed bushing. A brief description of the online monitoring system is presented, highlighting its superiority over conventional offline monitoring practices. This is followed by a true case study and a specimen cost-benefit analysis related to a failure of a 160 MVA, 220/132/33 kV transformer and its assumed do...
Hrčak ID: 202527


eng Dispersing the clouds: Gain clear insight into your bushings using advanced diagnostic methods
Anglhuber, Martin; Velásquez Contreras, Juan L.
Transformers Magazine Vol. 4, No. 5, 2017
Bushing diagnosis can include various methods, from a simple visual inspection or a conventional power/ dissipation factor measurement, to the latest high-tech broadband dielectric frequency response measurements. This article explains the different bushing insulation types and shows which problems can occur in bushings and which diagnostic methods can be used to detect them. Each measurement has its advantages and disadvantages and some are more suitable for onsite measurements, others for quality control of new bushings. Case studies show the...
Hrčak ID: 195046


eng Transformer bushings and oil leaks: A cost effective way to address oil and nitrogen leaks
Wickman, Steven H.
Transformers Magazine Vol. 4, No. 5, 2017
Many oil-filled large power transformers have been in service for years. One issue with aging transformers is addressing oil leaks. This article describes a cost-effective technique for repairing these oil leaks. Repairs can be made without draining the oil, or removing bushings. Often the repairs can be made with the transformer in service. This article presents the techniques used by a company that has been performing leak repairs on electric substation equipment since 1988, and works exclusively on electric substation equipment.
Hrčak ID: 202530


eng Internal arc testing of transformer bushings
Testin, Giovanni
Transformers Magazine Vol. 5, No. 1, 2018
This article discusses a special test on transformer bushings which has been introduced in the technical specifications of the Italian Transmission Operator. This test is used to increase the safety in case of an internal electric arc fault in a bushing, which might explode posing threat to human life and the surrounding equipment
Hrčak ID: 195251


eng Refining bushing power factor and capacitance analysis through statistics
Hernandez, Ronald D.; Lachman, Mark F.
Transformers Magazine Vol. 7, No. 3, 2020
Use of statistics opens the door for enhancing bushing power factor / capacitance analysis. The tool, in¬formed by a database with more than 6 million tests, tailors the diagnostic limits by determining what is sta¬tistically normal for a specific type, manufacturer, and voltage rating of a bushing. More precisely, it com¬putes deviations of power factor and capacitance from a benchmark. It then determines the probability dis¬tribution that best fits the resulting dataset. Once the data is mathemat¬ically characterized, the mean and standard de...
Hrčak ID: 242422


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 Overvoltages and Transients Identification In On-line Bushing Monitoring
Gil, Wieslaw; Masłowski, Wiktor; Wronek, Przemysław
Journal of Energy Vol. 69, No. 3, 2020
Overvoltages and transients are sometimes recognized as the cause of bushings’ rapid failure. This fact is confirmed by the studies published at the 2018 CIGRE session. They can also initiate dangerous resonance phenomena in transformer windings. The identification of very fast overvoltages characterized by high dynamics of voltage changes, so-called "transients", is difficult due to the limited frequency response of station voltage transformers. However, the bushing monitoring systems, based on the so-called "voltage method" can be used fo...
Hrčak ID: 247125