Correlation between Capacitance and Dissipation Factor used for Assessment of Stator Insulation
Measurements of capacitance C and dissipation
factor tand of the stator insulation system provide useful information
about internal defects within the insulation. The index k is defined as
the proportionality constant between the changes at high voltage of
capacitance DC and of the dissipation factor Dtand . DC and
Dtand values were highly correlated when small flat defects were
within the insulation and that correlation was lost in the presence of
large narrow defects like electrical treeing. The discrimination
between small and large defects is made resorting to partial discharge
PD phase angle analysis. For the validation of the results, C and tand
measurements were carried out in a 15MVA 4160V steam turbine
turbogenerator placed in a sugar mill. In addition, laboratory test
results obtained by other authors were analyzed jointly. In such
laboratory tests, model coil bars subjected to thermal cycling resulted
highly degraded and DC and Dtand values were not correlated. Thus,
the index k could not be calculated.
[1] C. Sumereder, "Statistical lifetime of hydro generators and failure
analysis," IEEE Trans. Dielectrics and Electrical Insulation, vol.15, pp.
678-685, June 2008.
[2] T. W. Dakin, "The Relation of Capacitance Increase with High Voltages
to Internal Electric Discharges and Discharging Void Volume," IEEE
Trans. Power Apparatus and Systems, Part III, vol.78, pp.790-794,
April 1959.
[3] M. Barnikas, Engineering Dielectrics, vol I. Baltimo, MD: ASTM, 1979,
pp. 22-25.
[4] P. Tavner, L. Ran, J. Penman, H. Sedding, Condition monitoring of
electrical machines. Gateshead, Tyne & Wear: Athenaeum Press Ltd,
2008, pp 13-50.
[5] L. Weixian, L. Jingliang, S. Wanfa, "Study of rapid thermal evaluation
for form-wound winding insulation systems," in Proc. 2nd Conf.
Properties and Applications of Dielectric Materials, Beijing, 1988, pp.
438-441.
[6] M. Kaufhold, K. Schafer, K. Bauer, A. Bethge, J. Risse, "Interface
phenomena in stator winding insulation ÔÇö challenges in design,
diagnosis, and service experience," IEEE Electrical Insulation
Magazine, vol. 18, pp. 27-36, 2002.
[7] T. Br├╝gger, "A New Test Method for Assessing the Impact of Thermal
Cycling on Hydrogenerator Stator Insulation," in Conf. Rec. 2010 IEEE
Int. Conf. Electrical Insulation and Dielectric Phenomena, pp. 1-4.
[8] G. C. Stone, M. Sasic, "Recent problems experienced with motor and
generator windings," in Conf. Rec. 2009 Petroleum and Chemical
Industry Conf. Annual Industry Applications Society, pp. 1-9.
[9] J. Zhidong, P. Xiang, G. Zhicheng, W. Liming, Y. Bo, "Evaluation of
the Degradation of Generator Stator Ground Wall Insulation Under
Multistresses Aging," IEEE Trans. Energy Conversion, vol. 23, pp.474-
483, June 2008.
[10] Y. Bo, Z. Zhelei, C. Xiaolin, X. Hengkun, "Study on the characteristic
parameters used to assess the insulation condition of stator winding," in
Proc. 7th Conf. Properties and Applications of Dielectric Materials,
Nagoya, 2003, pp. 278- 280.
[11] B. Sonerud, T. Bengtsson, J. Blennow, S.M. Gubanski, S. Nilsson,
"Capacitance measurements and tree length estimation during electrical
treeing in sub-picofarad samples," IEEE Trans. Dielectrics and
Electrical Insulation, vol. 16, pp.1707-1709, December 2009.
[12] R. Vogelsang, B. Fruth, K. Frohlich, "Detection of electrical tree
propagation in generator bar insulations by partial discharge
measurements," in Proc. 7th Conf. Properties and Applications of
Dielectric Materials, Nagoya, 2003, pp. 281- 285.
[13] Y. Bo, C. Xiaolin, C. Yonghong, S. Jiancheng, X. Hengkun, "Diagnosis
of stator winding insulation of large generator based on partial discharge
measurement," IEEE Trans. Energy Conversion, vol. 21, pp. 387- 395,
June 2006.
[14] M. Farahani, H. Borsi, E. Gockenbach, "Study of Capacitance and
Dissipation Factor Tip-Up to Evaluate the Condition of the Insulating
Systems for High Voltage Rotating Machines", Electrical Engineering,
vol. 89, pp. 263-270, March 2007.
[15] M. Farahani, E. Gockenbach, H. Borsi, M. Kaufhold, "Behavior of a
Machine Insulation System during Accelerated Aging Tests," in Conf.
Rec. 2008 IEEE Int. Symp. Electrical Insulation, pp.404-407.
[16] M. Farahani, E. Gockenbach, H. Borsi, M. Kaufhold, K. Schäfer,
"Behavior of machine insulation systems subjected to accelerated
thermal aging test," IEEE Trans. Dielectrics and Electrical Insulation,
vol.17, pp. 1364-1372, October 2010.
[17] H. Zhu, D. Kung, "Acoustic monitoring of insulation delaminations
during thermal cycling tests on a stator bar," in Conf. Rec. 2009 IEEE
Int. Conf. Electrical Insulation, pp.183-187.
[18] G.C. Stone, H.G. Sedding, B.A. Lloyd, B.K. Gupta, "The ability of
diagnostic tests to estimate the remaining life of stator insulation," IEEE
Trans. Energy Conversion, vol.3, pp.833-841, December 1988.
[1] C. Sumereder, "Statistical lifetime of hydro generators and failure
analysis," IEEE Trans. Dielectrics and Electrical Insulation, vol.15, pp.
678-685, June 2008.
[2] T. W. Dakin, "The Relation of Capacitance Increase with High Voltages
to Internal Electric Discharges and Discharging Void Volume," IEEE
Trans. Power Apparatus and Systems, Part III, vol.78, pp.790-794,
April 1959.
[3] M. Barnikas, Engineering Dielectrics, vol I. Baltimo, MD: ASTM, 1979,
pp. 22-25.
[4] P. Tavner, L. Ran, J. Penman, H. Sedding, Condition monitoring of
electrical machines. Gateshead, Tyne & Wear: Athenaeum Press Ltd,
2008, pp 13-50.
[5] L. Weixian, L. Jingliang, S. Wanfa, "Study of rapid thermal evaluation
for form-wound winding insulation systems," in Proc. 2nd Conf.
Properties and Applications of Dielectric Materials, Beijing, 1988, pp.
438-441.
[6] M. Kaufhold, K. Schafer, K. Bauer, A. Bethge, J. Risse, "Interface
phenomena in stator winding insulation ÔÇö challenges in design,
diagnosis, and service experience," IEEE Electrical Insulation
Magazine, vol. 18, pp. 27-36, 2002.
[7] T. Br├╝gger, "A New Test Method for Assessing the Impact of Thermal
Cycling on Hydrogenerator Stator Insulation," in Conf. Rec. 2010 IEEE
Int. Conf. Electrical Insulation and Dielectric Phenomena, pp. 1-4.
[8] G. C. Stone, M. Sasic, "Recent problems experienced with motor and
generator windings," in Conf. Rec. 2009 Petroleum and Chemical
Industry Conf. Annual Industry Applications Society, pp. 1-9.
[9] J. Zhidong, P. Xiang, G. Zhicheng, W. Liming, Y. Bo, "Evaluation of
the Degradation of Generator Stator Ground Wall Insulation Under
Multistresses Aging," IEEE Trans. Energy Conversion, vol. 23, pp.474-
483, June 2008.
[10] Y. Bo, Z. Zhelei, C. Xiaolin, X. Hengkun, "Study on the characteristic
parameters used to assess the insulation condition of stator winding," in
Proc. 7th Conf. Properties and Applications of Dielectric Materials,
Nagoya, 2003, pp. 278- 280.
[11] B. Sonerud, T. Bengtsson, J. Blennow, S.M. Gubanski, S. Nilsson,
"Capacitance measurements and tree length estimation during electrical
treeing in sub-picofarad samples," IEEE Trans. Dielectrics and
Electrical Insulation, vol. 16, pp.1707-1709, December 2009.
[12] R. Vogelsang, B. Fruth, K. Frohlich, "Detection of electrical tree
propagation in generator bar insulations by partial discharge
measurements," in Proc. 7th Conf. Properties and Applications of
Dielectric Materials, Nagoya, 2003, pp. 281- 285.
[13] Y. Bo, C. Xiaolin, C. Yonghong, S. Jiancheng, X. Hengkun, "Diagnosis
of stator winding insulation of large generator based on partial discharge
measurement," IEEE Trans. Energy Conversion, vol. 21, pp. 387- 395,
June 2006.
[14] M. Farahani, H. Borsi, E. Gockenbach, "Study of Capacitance and
Dissipation Factor Tip-Up to Evaluate the Condition of the Insulating
Systems for High Voltage Rotating Machines", Electrical Engineering,
vol. 89, pp. 263-270, March 2007.
[15] M. Farahani, E. Gockenbach, H. Borsi, M. Kaufhold, "Behavior of a
Machine Insulation System during Accelerated Aging Tests," in Conf.
Rec. 2008 IEEE Int. Symp. Electrical Insulation, pp.404-407.
[16] M. Farahani, E. Gockenbach, H. Borsi, M. Kaufhold, K. Schäfer,
"Behavior of machine insulation systems subjected to accelerated
thermal aging test," IEEE Trans. Dielectrics and Electrical Insulation,
vol.17, pp. 1364-1372, October 2010.
[17] H. Zhu, D. Kung, "Acoustic monitoring of insulation delaminations
during thermal cycling tests on a stator bar," in Conf. Rec. 2009 IEEE
Int. Conf. Electrical Insulation, pp.183-187.
[18] G.C. Stone, H.G. Sedding, B.A. Lloyd, B.K. Gupta, "The ability of
diagnostic tests to estimate the remaining life of stator insulation," IEEE
Trans. Energy Conversion, vol.3, pp.833-841, December 1988.
@article{"International Journal of Electrical, Electronic and Communication Sciences:58032", author = "José Luis Oslinger and Luis Carlos Castro", title = "Correlation between Capacitance and Dissipation Factor used for Assessment of Stator Insulation", abstract = "Measurements of capacitance C and dissipation
factor tand of the stator insulation system provide useful information
about internal defects within the insulation. The index k is defined as
the proportionality constant between the changes at high voltage of
capacitance DC and of the dissipation factor Dtand . DC and
Dtand values were highly correlated when small flat defects were
within the insulation and that correlation was lost in the presence of
large narrow defects like electrical treeing. The discrimination
between small and large defects is made resorting to partial discharge
PD phase angle analysis. For the validation of the results, C and tand
measurements were carried out in a 15MVA 4160V steam turbine
turbogenerator placed in a sugar mill. In addition, laboratory test
results obtained by other authors were analyzed jointly. In such
laboratory tests, model coil bars subjected to thermal cycling resulted
highly degraded and DC and Dtand values were not correlated. Thus,
the index k could not be calculated.", keywords = "Aging, capacitance, dissipation factor, electrical
treeing, insulation condition, partial discharge.", volume = "6", number = "3", pages = "320-7", }
