Analysis of Insulation Quality in Large Generator Stator Windings

Kim, Hee‐Dong; Kong, Tae‐Sik; Ju, Yang; Kim, Byong-Han

doi:10.5370/jeet.2011.6.2.384

Cited by 12 publications

(10 citation statements)

References 6 publications

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“…Because these test measure the current and dissipation factor of the whole insulation system, it is used to find the average deterioration condition of the insulation material. [1,9,10]…”

Section: Fig 2 Test Circuit Of Partial Dischargementioning

confidence: 99%

Analysis of Generator Stator Remaining Breakdown Voltage for Power Plant

Kim¹

2016

EPES

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The reliability of stator windings is very important for stable operation of generators, while they are under thermal, mechanical, environmental, and electrical stresses over years of operation. Utility companies are very interested in the remaining breakdown voltage of generators and utilize the corresponding data for maintenance or replacement of generators. In most cases the remaining breakdown voltage is measured by performing a non-destructive dielectric strength test. In this paper, the remaining breakdown voltage of a generator is predicted using statistical methods by comparison with actual measured data, considering the cooling method, maker, and years of use of generators, as a means to supplement the existing methods. This method can be used to minimize the errors that may occur when only the dielectric strength test is used.

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“…Because these test measure the current and dissipation factor of the whole insulation system, it is used to find the average deterioration condition of the insulation material. [1,9,10]…”

Section: Fig 2 Test Circuit Of Partial Dischargementioning

confidence: 99%

Analysis of Generator Stator Remaining Breakdown Voltage for Power Plant

Kim¹

2016

EPES

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“…Several studies were conducted to evaluate the condition of stator winding insulation and analyze the effects of deteriorating factors on insulation system under accelerated aging process [4,5].…”

Section: Introductionmentioning

confidence: 99%

“…This test is only infrequently applied, however [6,7]. In general, to diagnose HV motors used in domestic industrial sites, test voltages are limited to within the rated voltage, and insulation resistance, polarization index, alternating current, dissipation factor, and partial discharge tests are usually conducted [8].…”

Section: Introductionmentioning

confidence: 99%

Changes in Insulation Characteristics of High-Voltage Motor Stator Windings with Temperature and Moisture

Kong¹

2018

EPES

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This research shows that all of the insulation characteristics (insulation resistance, partial discharge, dissipation factor, and alternating leakage current) of HV motor become worse at high temperature. It is also shows that partial discharge and insulation resistance are reduced at moisture absorption. Therefore, to accurately analyze the insulation degradation trend, it is necessary that those tests always be conducted under the same conditions (temperature and moisture content).

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“…Some commonly used off-line tests for verifying the condition of the insulation include the insulation resistance, polarization index (PI), AC current, dissipation factor, and partial discharge (PD) tests whose results are comprehensively analyzed to evaluate the overall insulation deterioration. These diagnostic tests are also performed regularly in Korea for assessing the insulation condition of generator stator windings, and the Japanese deterioration judgment criterion has been used for assessment [3,4].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Insulation Diagnosis and Failure in Gas Turbine Generator Stator Windings

Kim¹

2014

Journal of Electrical Engineering and Technology

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-In order to evaluate the insulation deterioration in the stator windings of five gas turbine generators(137 MVA, 13.8 kV) which has been operated for more than 13 years, diagnostic test and AC dielectric breakdown test were performed at phases A, B and C. These tests included measurements of AC current, dissipation factor, partial discharge (PD) magnitude and capacitance. ΔI and Δtanδ in all three phases (A, B and C) of No. 1 generator stator windings showed that they were in good condition but PD magnitude indicated marginally serviceable and bad level to the insulation condition. Overall analysis of the results suggested that the generator stator windings were indicated serious insulation deterioration and patterns of the PD in all three phases were analyzed to be internal, slot and spark discharges. After the diagnostic test, an AC overvoltage test was performed by gradually increasing the voltage applied to the generator stator windings until electrical insulation failure occurred, in order to determine the breakdown voltage. The breakdown voltage at phases A, B and C of No. 1 generator stator windings failed at 28.0 kV, 17.9 kV, and 21.3 kV, respectively. The breakdown voltage was lower than that expected for good-quality windings (28.6 kV) in a 13.8kV class generator. In the AC dielectric breakdown and diagnostic tests, there was a strong correlation between the breakdown voltage and the voltage at which charging current increases abruptly (P i1 , P i2 ).

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Analysis of Insulation Quality in Large Generator Stator Windings

Cited by 12 publications

References 6 publications

Analysis of Generator Stator Remaining Breakdown Voltage for Power Plant

Analysis of Generator Stator Remaining Breakdown Voltage for Power Plant

Changes in Insulation Characteristics of High-Voltage Motor Stator Windings with Temperature and Moisture

Characteristics of Insulation Diagnosis and Failure in Gas Turbine Generator Stator Windings

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