A New High-Voltage Insulation for Turbine-Generator Stator Windings

Laffoon, C. M.; Hill, C. F.; Moses, G. L.; Berberich, L. J.

doi:10.1109/t-aiee.1951.5060468

Cited by 36 publications

(3 citation statements)

References 7 publications

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“…Both were immediately considered as possible material for the insulation of electrical machines. In 1949, Westinghouse used mica-tape and polyester resin in its insulation system [24]. General-Electric follows them two years later.…”

Section: Bonding Material: the Epoxy Resin The Weakest Part Of The Imentioning

confidence: 99%

The Insulation for Machines Having a High Lifespan Expectancy, Design, Tests and Acceptance Criteria Issues

Barré¹,

Napame²

2017

Machines

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Abstract:The windings insulation of electrical machines will remain a topic that is updated frequently. The criteria severity requested by the electrical machine applications increases continuously. Manufacturers and designers are always confronted with new requirements or new criteria with enhanced performances. The most problematic requirements that will be investigated here are the extremely long lifespan coupled to critical operating conditions (overload, supply grid instabilities, and critical operating environments). Increasing lifespan does not have a considerable benefit because the purchasing price of usual machines has to be compared to the purchasing price and maintenance price of long lifespan machines. A machine having a 40-year lifespan will cost more than twice the usual price of a 20-year lifetime machine. Systems which need a long lifetime are systems which are crucial for a country, and those for which outage costs are exorbitant. Nuclear power stations are such systems. It is certain that the used technologies have evolved since the first nuclear power plant, but they cannot evolve as quickly as in other sectors of activities. No-one wants to use an immature technology in such power plants. Even if the electrical machines have exceeded 100 years of age, their improvements are linked to a patient and continuous work. Nowadays, the windings insulation systems have a well-established structure, especially high voltage windings. Unfortunately, a high life span is not only linked to this result. Several manufacturers' improvements induced by many years of experiment have led to the writing of standards that help the customers and the manufacturers to regularly enhance the insulation specifications or qualifications. Hence, in this publication, the authors will give a step by step exhaustive review of one insulation layout and will take time to give a detailed report on the standards that are linked to insulation systems. No standard can provide insurance about lifespan, nor do any insulation tests incorporate all of the operating conditions: thermal, mechanical, moisture and chemical. Even if one manufacturer uses the standards compliance to demonstrate the quality of its realization; in the end, the successful use in operation remains an objective test. Thereafter, both customer and manufacturers will use the standards while knowing that such documents cannot fully satisfy their wishes. In one 20-year historical review, the authors will highlight the duration in insulation improvements and small breakthroughs in standards writing. High lifespan machines are not the main interest of standards. A large part of this publication is dedicated to the improvements of the insulation wall to achieve the lifespan. Even if the choice of raw materials is fundamental, the understanding of ageing phenomena also leads to improvements.

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Section: Bonding Material: the Epoxy Resin The Weakest Part Of The Imentioning

confidence: 99%

The Insulation for Machines Having a High Lifespan Expectancy, Design, Tests and Acceptance Criteria Issues

Barré¹,

Napame²

2017

Machines

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“…98 "" 106 The polyesters were the first suitable synthetic resins, and the earliest (1951) of the new insulation systems was based on these. 99 The silicones were also considered, but as these are more difficult to process and are expensive they are not used in turbogenerators. The latest group to be developed, the epoxides, have proved to be the most versatile, and resins in one or other of the subgroups, particularly epoxy novolak and cycloaliphatic, are now widely used either alone or sometimes in conjunction with a polyester.…”

Section: Stator Windingsmentioning

confidence: 99%

Recent trends in turbogenerators

Vickers¹

1974

Proc. Inst. Electr. Eng. UK

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The paper begins with an historical account of the evolution of the turbogenerator, emphasing the landmarks in its development. Against the background of probable future requirements, a critical assessment is made of current design philosophies and their limitations are examined. The barriers to advancement in technology, in materials, and in physical size and weight are identified and the resulting trends in design investigated. The interdependence of generator and transmission-system characteristics is considered in relation to likely advances in generator design. The problem areas of stator core and winding vibration and core-end heating are reviewed. Developments in structural materials, cooling systems, insulation and handling and transport are covered. Recent developments in excitation systems, notably in the 'brushless' concept, that have obviated the need for sliprings are also examined. The final section includes a review of the potential advantages and practical problems associated with the possible use of design principles involving increasingly radical departures from current established practice. These progress from the completely liquid-cooled machine without hydrogen, prototypes of which have already been manufactured, through the more or less conventional generator but with stator and rotor windings accommodated in the airgap, to designs using evaporative and cryogenic cooling principles. An extensive bibliography is included.

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“…One way to achieve the desired improvement is to use composite materials [4] where the synergy effect of individual components is utilized. In the field of insulating systems for rotating machines, there are, in particular, three component composite materials, which are composed of a matrix, filler and reinforcement [5].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Diagnostics of Nanostructured Micaless Microcomposite as a Prospective Insulation Material for Rotating Machines

et al. 2019

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This paper deals with the topic of composite insulation materials for rotating machines and it is primarily pointed to the synthesis of new three-component insulation system. In connection with this research, the basic components of the insulation system are selected and described by different diagnostic methods. The proposed insulation material is composed of epoxy resin based on bisphenol-A diglycidyl ether, magnesium oxide nanofiller (1 wt %) with its own surface treatment technology using epoxysilane coupling agent ( γ -glycidoxypropyltrimethoxysilane) and polyethylene naphthalate as a reinforcing component. Following the defined topic of the paper, the proposed three-component insulation system is confronted with commonly used insulating systems (PET reinforced and Glass reinforced mica composites) in order to verify the basic dielectric properties (dielectric strength, volume resistivity, dissipation factor) and other parameters determined from phenomenological voltage and current signals, respectively.

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A New High-Voltage Insulation for Turbine-Generator Stator Windings

Cited by 36 publications

References 7 publications

The Insulation for Machines Having a High Lifespan Expectancy, Design, Tests and Acceptance Criteria Issues

The Insulation for Machines Having a High Lifespan Expectancy, Design, Tests and Acceptance Criteria Issues

Recent trends in turbogenerators

Synthesis and Diagnostics of Nanostructured Micaless Microcomposite as a Prospective Insulation Material for Rotating Machines

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