The principles of obtaining stable semiconducting compositions and reliable anti-corona designs for high voltage windings

This paper covers the work carried out at the Research and Development Department of the plant ldquoElectrotyazhmashrdquo, Ukraine for developing reliable anti-corona systems for high voltage generator windings up to 24 kV. The work included estimating the necessity of application of the slot parts semiconducting system and calculation of its parameters; developing the anti-corona protection design for the end turns of windings that would be reliable in the manufacture and in operation at Power Stations; and developing stable semiconducting materials for anti-corona design realization. The main principles of obtaining reliable anti-corona designs and stable semiconducting composition were elaborated. The developed anti-corona system was implemented on turbo generators of power 200, 300, and 500 MW with windings of 15.75, 20 and 24 kV, hydro generators of 20...400 MW with windings of 13.8 and 15.75 kV, and pump motor generators of 40, 210 and 420 MW with windings of 10.5 and 15.75 kV. All generators have been working successfully in operation. The Power Stations (and plant "Electrotyazhmash") have not had any problems with the slot discharges or visual corona and discharges on end turn of windings for last 30 years that the generators with developed anti-corona system have been in use.