IEEE 436-1991 pdf free.IEEE Guide for Making Corona (PartialDischarge)Measurements on Electronics Transformers.
Corona (partial discharge) is an ionizationphenomenon that can cause deterioration incertain insulation systems. Its presence inelectronic equipment can be harmful throughits manifestation as cireuit noise，spuriousvoltage or current pulses, or other undesirableeffects that lead to circuit malfunctions.Transformers and inductors used in elec-tronic circuits at high voltages can be locations where this harmful phenomenon originates. Even in instances where dischargesare not of concern in circuit performance, theymay be of concern because of their adverse effect on component life. It is,therefore,essential that the insulation system be free of coronadischarges at operating voltage stresses.Themagnitude or intensity of these discharges isusually of such a low level that very sensitiveelectronic measuring apparatus and techniques are required to detect them.
IEEE 436 a uniform procedure formaking corona (partial discharge) measure-ments by electrical means onelectronics
transformers. Methods of applying voltagestress, the use of a sinewave voltage to simulate dc and ac combinations,the types andlimitations of voltage stresses encountered,and the acceptable limits of discharge pulseenergy are included. Recommended test conditions and the need for negotiation of specialtests are discussed.
Application of This Guide.The test condi-tions applicable to electronics transformersinclude all the configuration and circuit ar-rangements used in power transformers and,in addition，include a large number of induc-tive devices with special circuit characteris-tics and with electrical stress on insulationcovering the entire range of frequencies from dc through microwave and all combinations ofthese frequencies.At the present time,thisguide will be limited to detection and measurements with sine-wave applied voltageranging in frequeney from zero to approxi-mately 2000 Hz.The detection and measure-ment of corona discharges with appliedvoltages at higher frequencies orwith nonsinusoidal wave shapes requires specialtechniques，since the discharge pulse itselfalso has a wide frequency spectrum,a portion of which may fail within the operatingfrequency range.
Conditions for Acceptable Corona Tests.The duplication of the exact voltage stressesthat occur in service，including frequenciesand transients，is acknowledged to result inthe most accurate corona discharge measure-ments; however，insistence on exact conditions may be impractical. The fundamentalconditions for acceptable corona tests arebased on the assumptions and limitations thatfollow.IEEE 436 pdf download.