Jean-Pierre Crine - Academia.edu (original) (raw)
Papers by Jean-Pierre Crine
J. Non Cryst. Sol., 2025
Applying Eyring equation to experimental data for the relaxation of glassy dielectrics shows th... more Applying Eyring equation to experimental data for the relaxation of glassy dielectrics shows the fundamental role of activation entropy in relaxation dynamics. The combination of Eyring equation and compensation law provides access to other important parameters, such as the compensation temperature and absolute value of the configurational activation entropy in the Arrhenius regime. The non-linear behavior observed at low temperatures is explained by the time and temperature variations in the configurational activation entropy, SC. We propose that this change corresponds to rarefaction of free equilibrium states as T is lowered. A simple method was proposed to calculate SC from the change in free energy in the non linear regime. The lowest temperature limit of the relaxation is not known, but it seems unlikely that it is the VTF or Kauzmann temperatures. Brief comments on the physical significance of these two parameters were provided. It is also shown that relaxation times are not invariant, as suggested.
The 17th Annual Meeting of the IEEE Lasers and Electro-Optics Society, 2004. LEOS 2004.
ABSTRACT A model for the electrical aging of cable insulation has already been presented by one o... more ABSTRACT A model for the electrical aging of cable insulation has already been presented by one of the authors. It appears that the experimental results of rotating machine aging obey a semi-log relation between the square of the applied field and the log of time, as predicted by our aging model. The slope of such plots is related to the so-called activation volume of the aging process, that is, to the stressed volume. The intercept in the semi-log plots is related to the activation energy of the process. These two basic parameters depend on the insulation nature, morphology and on several other parameters especially temperature. The identification and exact role of these unknown parameters require further work but the fact that the fundamental aspects of our aging model apply to this specific case suggest that it could be possible to use the model for more reliable life prediction for rotating machines. Suggestions for further experimental and theoretical work is briefly discussed.
Conference on Electrical Insulation and Dielectric Phenomena
ABSTRACT
IEEE Transactions on Electrical Insulation, 1988
It is shown that particle deposition in transformer oil samples taken in power equipment operated... more It is shown that particle deposition in transformer oil samples taken in power equipment operated under service conditions is relatively rapid. The particle counts, the metal-in-oil contents and the breakdown voltage of such samples vary significantly with the deposition time of particles. A simple and inexpensive homogenization method based on ultrasonic agitation is proposed. It is shown that 25 min. of ultrasonic agitation is sufficient to restore the original particle distribution in oil samples. This also leads to a modified and more realistic breakdown voltage value. >
2001 IEEE/PES Transmission and Distribution Conference and Exposition. Developing New Perspectives (Cat. No.01CH37294)
ABSTRACT The condition assessment of paper insulated lead covered cables (PILC) cables is a cruci... more ABSTRACT The condition assessment of paper insulated lead covered cables (PILC) cables is a crucial factor for many utilities and this paper is devoted to the evaluation of some new diagnostic techniques enabling users to effectively manage their PILC cable assets. We used electrical, metallurgical and chemical techniques to measure the electrical, chemical, dielectric and metallurgical properties of paper-impregnated insulation. The nondestructive electrical tests performed on three full-length field-aged PILC cables were: the isothermal relaxation current (IRC), the LIpATEST leakage current test and the return voltage method (RVM). Chemical tests were performed on small samples of paper tapes and oil taken from the same samples. They were: dielectric analysis, Fourier transform infra red (FTIR) spectroscopy and moisture content analysis. The electrical techniques ranked the cables consistently, that is one cable aged 23 years seemed to be more severely aged than the older (34 years) and younger (4 years) cables. This could possibly be explained by the acids detected in the oil of the 23 year old cable using FTIR spectroscopy. Although more data on more cables would be needed it already appears that the tested techniques could assess the condition of the insulation of PILC cables. Water ingress is often associated with cracks in the lead sheaths due to fatigue and creep failure. Metallurgical tests were performed on the lead sheaths of four PILC cables and they revealed that artificial cracks of different depths introduced on the surface of the lead sheaths were easily detected by the visual and fluorescent dye penetrant inspections. An eddy current inspection technique was successful in detecting the artificial surface flaws on the lead sheaths. The hardness of the older lead sheath, as measured by the Brinell test, tends to be lower than that of the lead sheath of the younger vintage cables
Proceedings of the 2004 IEEE International Conference on Solid Dielectrics, 2004. ICSD 2004.
Moisture content titration, using the Karl-Fischer method, was performed on small samples of pape... more Moisture content titration, using the Karl-Fischer method, was performed on small samples of paper tapes taken from thirteen full-length field-aged distribution paper insulated lead covered (PILC) cables. It has often been suggested in the literature that the moisture content of paper-oil systems could be estimated from some electrical and dielectric measurements, especially from return voltage and from dielectric spectroscopy measurements.
The 17th Annual Meeting of the IEEE Lasers and Electro-Optics Society, 2004. LEOS 2004.
It is well known that there is a compensation law between the change of enthalpy and change of en... more It is well known that there is a compensation law between the change of enthalpy and change of entropy associated with the relaxations of several polymers. We have already suggested that the temperatures of transition from one relaxation to another correspond to a thermodynamic transition. In this paper, we show that the slope of the compensation law is the inverse of the transition temperatures of various polymers (PVC, PTFE, PP, PS, etc.). It is also shown that within the transition temperatures range, the relaxations of the studied polymers are single relaxation time processes. In other words, there is no need for complex (and often unexplained) distribution of relaxation times. It is often suggested that dielectric and mechanical relaxation measurements give similar information on the studied relaxations. A detailed analysis of the Gibbs free activation energy of several results indicate that this is not entirely true. The activation energy (not to be confused with the so-called energy of activation deduced from Arrhenius plots) of the dielectric measurements are systematically lower than those deduced from mechanical measurements.
Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics
ABSTRACT
2008 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2008
ABSTRACT We have shown elsewhere that the Eyring equation can describe the electrical aging of se... more ABSTRACT We have shown elsewhere that the Eyring equation can describe the electrical aging of several polymers. This equation has two main activated parameters, namely the activated energy DeltaG and the activated volume DeltaV. In this paper, we confirm our previous supposition that DeltaG is related to the C-C bond strength by providing examples deduced from the electrical aging of polyethylene and polypropylene. We can now identify the origin and nature of the activated volume DeltaV for aging and breakdown of polymers. It is shown to be somehow associated with the concentration of broken bonds and on the maximum concentration of free charges in the aged sample. With the understanding of the physical sense of the two activated parameters, it is now possible to predict the life equation of simple insulating polymers from their basic physico-chemical properties. The significance of these calculations on the interpretation of other electrical properties is also briefly discussed.
Canadian Electrical Engineering Journal, 1986
A brief critical review of the electrical, thermal and flammability properties of silicone oil fo... more A brief critical review of the electrical, thermal and flammability properties of silicone oil for transformers is presented in comparison to the same properties for polychlorinated biphenyl fluids (PCB) and mineral oil. It is deduced that silicone oil is an acceptable substitute for PCBs. Despite a significantly lower fire resistance, silicone oil is not toxic and is compatible with traces of PCBs and mineral oil. It is therefore perfectly suited for the retrofilling of PCB contaminated transformers.
IEEE Transactions on Electrical Insulation, 1991
Proceedings of 1994 IEEE International Symposium on Electrical Insulation
XLPE insulation used in high-voltage cables is not only subjected to electrical stress but also t... more XLPE insulation used in high-voltage cables is not only subjected to electrical stress but also to mechanical strains, either from internal residual strains created during manufacturing or externally applied when the cable is bent sharply. Due to thermally activated viscoelastic motion in the polymeric material, the original mechanical stress responsible for the strain may be completely or partly relaxed, with the permanent strain remaining unchanged. It is generally accepted that mechanical strain has a strong influence on the structural integrity and electrical performance of polymeric insulating materials. However, the influence of mechanical strain on the life and performance of insulating materials has still to be fully ascertained, since it depends on the nature (compression or tensile) and the direction of the strain and the magnitude of the remaining (unrelaxed) mechanical stress. In this paper, long-term and short-term breakdown tests were conducted on XLPE ribbon samples. To isolate the effect of the strain, a series of samples was drawn at different drawing ratios; the drawing rate and temperature allowed a situation of near-total stress relaxation. Results are presented for samples subjected to simultaneous tensile mechanical and electrical stress
[1992] Proceedings of the 4th International Conference on Conduction and Breakdown in Solid Dielectrics
Conference Record of the 1992 IEEE International Symposium on Electrical Insulation
[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena
The authors report infrared (IR) absorption measurements conducted on laboratory-aged and unaged ... more The authors report infrared (IR) absorption measurements conducted on laboratory-aged and unaged cross-linked polyethylene (XLPE) cable samples. Variations in the IR absorbance of the methyl group (1377 cm -1) and the carbonyl groups (~1700 cm-1) were recorded as a function of both radial and angular coordinates for the samples. These variations were found to be strongly correlated with optical birefringence
2009 IEEE Conference on Electrical Insulation and Dielectric Phenomena, 2009
ABSTRACT In this paper, we address some poorly explained problems associated with electrical prop... more ABSTRACT In this paper, we address some poorly explained problems associated with electrical properties of dielectric polymers. Charge injection is often unclear due to metal-polymer interfaces phenomena including poor contacts, asperities and electrochemical reactions. We also review some difficulties involving the sample bulk, the most important being the influence of the sample size on aging and breakdown. We show many results obtained with a wide variety of (reasonably pure and defect-free) polymers suggesting that in addition to thickness, the electrodes area is also a parameter. The negative resistance often observed in conductivity measurements is also discussed. The fact that C-C bonds are more easily broken than expected implies that this phenomenon must be looked at more carefully. The role of the free radicals thus created requires more attention. It is suggested that the interpretation of several measurements, mobility for example, might require some revision. Among other things, interpreting results using only an activation energy is not likely to give a correct description of the measured phenomenon since entropie effects are quite significant with most polymers. Finally, one may wonder if the usual explanation for some trapped sites in the so-called forbidden band of polyethylene still makes sense considering the fact that charge transport is mainly affected by the bonds broken by the applied stress.
2007 Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, 2007
ABSTRACT We show that our new aging concept describes the electrical aging process of XLPE and, i... more ABSTRACT We show that our new aging concept describes the electrical aging process of XLPE and, in fact applies to all polymers with free volume. The physical significance of the basic parameters (activation energy and volume) is discussed and it is shown that XLPE cable aging directly depends on the breaking of C-C bonds. The influence of samples size is briefly discussed as well as the influence of free radicals.
IEEE International Symposium on Electrical Insulation
ABSTRACT
1991 Annual Report. Conference on Electrical Insulation and Dielectric Phenomena,
ABSTRACT First Page of the Article
2000 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.00CH37132)
ABSTRACT Water treeing depends on many parameters, especially frequency. We have reviewed the lit... more ABSTRACT Water treeing depends on many parameters, especially frequency. We have reviewed the literature for water trees grown in polyethylene soaked at room temperature in distilled water and various NaCl solutions. All existing data obtained with water needle electrodes (Ascraft cells) obey one single relationship between water-tree length and the number of field cycles, i.e. the frequency×time. The upper frequency limit of this process appears to be in the 30 kHz range. The effect of ion concentration is more influential for a large number of field cycles (above 108 cycles), but is not as significant as the frequency effect. The field calculated at water needle defect, ranging from 80 to 600 kV/mm, has little influence on water tree length. The practical impact of these observations is briefly discussed
J. Non Cryst. Sol., 2025
Applying Eyring equation to experimental data for the relaxation of glassy dielectrics shows th... more Applying Eyring equation to experimental data for the relaxation of glassy dielectrics shows the fundamental role of activation entropy in relaxation dynamics. The combination of Eyring equation and compensation law provides access to other important parameters, such as the compensation temperature and absolute value of the configurational activation entropy in the Arrhenius regime. The non-linear behavior observed at low temperatures is explained by the time and temperature variations in the configurational activation entropy, SC. We propose that this change corresponds to rarefaction of free equilibrium states as T is lowered. A simple method was proposed to calculate SC from the change in free energy in the non linear regime. The lowest temperature limit of the relaxation is not known, but it seems unlikely that it is the VTF or Kauzmann temperatures. Brief comments on the physical significance of these two parameters were provided. It is also shown that relaxation times are not invariant, as suggested.
The 17th Annual Meeting of the IEEE Lasers and Electro-Optics Society, 2004. LEOS 2004.
ABSTRACT A model for the electrical aging of cable insulation has already been presented by one o... more ABSTRACT A model for the electrical aging of cable insulation has already been presented by one of the authors. It appears that the experimental results of rotating machine aging obey a semi-log relation between the square of the applied field and the log of time, as predicted by our aging model. The slope of such plots is related to the so-called activation volume of the aging process, that is, to the stressed volume. The intercept in the semi-log plots is related to the activation energy of the process. These two basic parameters depend on the insulation nature, morphology and on several other parameters especially temperature. The identification and exact role of these unknown parameters require further work but the fact that the fundamental aspects of our aging model apply to this specific case suggest that it could be possible to use the model for more reliable life prediction for rotating machines. Suggestions for further experimental and theoretical work is briefly discussed.
Conference on Electrical Insulation and Dielectric Phenomena
ABSTRACT
IEEE Transactions on Electrical Insulation, 1988
It is shown that particle deposition in transformer oil samples taken in power equipment operated... more It is shown that particle deposition in transformer oil samples taken in power equipment operated under service conditions is relatively rapid. The particle counts, the metal-in-oil contents and the breakdown voltage of such samples vary significantly with the deposition time of particles. A simple and inexpensive homogenization method based on ultrasonic agitation is proposed. It is shown that 25 min. of ultrasonic agitation is sufficient to restore the original particle distribution in oil samples. This also leads to a modified and more realistic breakdown voltage value. >
2001 IEEE/PES Transmission and Distribution Conference and Exposition. Developing New Perspectives (Cat. No.01CH37294)
ABSTRACT The condition assessment of paper insulated lead covered cables (PILC) cables is a cruci... more ABSTRACT The condition assessment of paper insulated lead covered cables (PILC) cables is a crucial factor for many utilities and this paper is devoted to the evaluation of some new diagnostic techniques enabling users to effectively manage their PILC cable assets. We used electrical, metallurgical and chemical techniques to measure the electrical, chemical, dielectric and metallurgical properties of paper-impregnated insulation. The nondestructive electrical tests performed on three full-length field-aged PILC cables were: the isothermal relaxation current (IRC), the LIpATEST leakage current test and the return voltage method (RVM). Chemical tests were performed on small samples of paper tapes and oil taken from the same samples. They were: dielectric analysis, Fourier transform infra red (FTIR) spectroscopy and moisture content analysis. The electrical techniques ranked the cables consistently, that is one cable aged 23 years seemed to be more severely aged than the older (34 years) and younger (4 years) cables. This could possibly be explained by the acids detected in the oil of the 23 year old cable using FTIR spectroscopy. Although more data on more cables would be needed it already appears that the tested techniques could assess the condition of the insulation of PILC cables. Water ingress is often associated with cracks in the lead sheaths due to fatigue and creep failure. Metallurgical tests were performed on the lead sheaths of four PILC cables and they revealed that artificial cracks of different depths introduced on the surface of the lead sheaths were easily detected by the visual and fluorescent dye penetrant inspections. An eddy current inspection technique was successful in detecting the artificial surface flaws on the lead sheaths. The hardness of the older lead sheath, as measured by the Brinell test, tends to be lower than that of the lead sheath of the younger vintage cables
Proceedings of the 2004 IEEE International Conference on Solid Dielectrics, 2004. ICSD 2004.
Moisture content titration, using the Karl-Fischer method, was performed on small samples of pape... more Moisture content titration, using the Karl-Fischer method, was performed on small samples of paper tapes taken from thirteen full-length field-aged distribution paper insulated lead covered (PILC) cables. It has often been suggested in the literature that the moisture content of paper-oil systems could be estimated from some electrical and dielectric measurements, especially from return voltage and from dielectric spectroscopy measurements.
The 17th Annual Meeting of the IEEE Lasers and Electro-Optics Society, 2004. LEOS 2004.
It is well known that there is a compensation law between the change of enthalpy and change of en... more It is well known that there is a compensation law between the change of enthalpy and change of entropy associated with the relaxations of several polymers. We have already suggested that the temperatures of transition from one relaxation to another correspond to a thermodynamic transition. In this paper, we show that the slope of the compensation law is the inverse of the transition temperatures of various polymers (PVC, PTFE, PP, PS, etc.). It is also shown that within the transition temperatures range, the relaxations of the studied polymers are single relaxation time processes. In other words, there is no need for complex (and often unexplained) distribution of relaxation times. It is often suggested that dielectric and mechanical relaxation measurements give similar information on the studied relaxations. A detailed analysis of the Gibbs free activation energy of several results indicate that this is not entirely true. The activation energy (not to be confused with the so-called energy of activation deduced from Arrhenius plots) of the dielectric measurements are systematically lower than those deduced from mechanical measurements.
Proceedings of the 3rd International Conference on Conduction and Breakdown in Solid Dielectrics
ABSTRACT
2008 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2008
ABSTRACT We have shown elsewhere that the Eyring equation can describe the electrical aging of se... more ABSTRACT We have shown elsewhere that the Eyring equation can describe the electrical aging of several polymers. This equation has two main activated parameters, namely the activated energy DeltaG and the activated volume DeltaV. In this paper, we confirm our previous supposition that DeltaG is related to the C-C bond strength by providing examples deduced from the electrical aging of polyethylene and polypropylene. We can now identify the origin and nature of the activated volume DeltaV for aging and breakdown of polymers. It is shown to be somehow associated with the concentration of broken bonds and on the maximum concentration of free charges in the aged sample. With the understanding of the physical sense of the two activated parameters, it is now possible to predict the life equation of simple insulating polymers from their basic physico-chemical properties. The significance of these calculations on the interpretation of other electrical properties is also briefly discussed.
Canadian Electrical Engineering Journal, 1986
A brief critical review of the electrical, thermal and flammability properties of silicone oil fo... more A brief critical review of the electrical, thermal and flammability properties of silicone oil for transformers is presented in comparison to the same properties for polychlorinated biphenyl fluids (PCB) and mineral oil. It is deduced that silicone oil is an acceptable substitute for PCBs. Despite a significantly lower fire resistance, silicone oil is not toxic and is compatible with traces of PCBs and mineral oil. It is therefore perfectly suited for the retrofilling of PCB contaminated transformers.
IEEE Transactions on Electrical Insulation, 1991
Proceedings of 1994 IEEE International Symposium on Electrical Insulation
XLPE insulation used in high-voltage cables is not only subjected to electrical stress but also t... more XLPE insulation used in high-voltage cables is not only subjected to electrical stress but also to mechanical strains, either from internal residual strains created during manufacturing or externally applied when the cable is bent sharply. Due to thermally activated viscoelastic motion in the polymeric material, the original mechanical stress responsible for the strain may be completely or partly relaxed, with the permanent strain remaining unchanged. It is generally accepted that mechanical strain has a strong influence on the structural integrity and electrical performance of polymeric insulating materials. However, the influence of mechanical strain on the life and performance of insulating materials has still to be fully ascertained, since it depends on the nature (compression or tensile) and the direction of the strain and the magnitude of the remaining (unrelaxed) mechanical stress. In this paper, long-term and short-term breakdown tests were conducted on XLPE ribbon samples. To isolate the effect of the strain, a series of samples was drawn at different drawing ratios; the drawing rate and temperature allowed a situation of near-total stress relaxation. Results are presented for samples subjected to simultaneous tensile mechanical and electrical stress
[1992] Proceedings of the 4th International Conference on Conduction and Breakdown in Solid Dielectrics
Conference Record of the 1992 IEEE International Symposium on Electrical Insulation
[Proceedings] 1992 Annual Report: Conference on Electrical Insulation and Dielectric Phenomena
The authors report infrared (IR) absorption measurements conducted on laboratory-aged and unaged ... more The authors report infrared (IR) absorption measurements conducted on laboratory-aged and unaged cross-linked polyethylene (XLPE) cable samples. Variations in the IR absorbance of the methyl group (1377 cm -1) and the carbonyl groups (~1700 cm-1) were recorded as a function of both radial and angular coordinates for the samples. These variations were found to be strongly correlated with optical birefringence
2009 IEEE Conference on Electrical Insulation and Dielectric Phenomena, 2009
ABSTRACT In this paper, we address some poorly explained problems associated with electrical prop... more ABSTRACT In this paper, we address some poorly explained problems associated with electrical properties of dielectric polymers. Charge injection is often unclear due to metal-polymer interfaces phenomena including poor contacts, asperities and electrochemical reactions. We also review some difficulties involving the sample bulk, the most important being the influence of the sample size on aging and breakdown. We show many results obtained with a wide variety of (reasonably pure and defect-free) polymers suggesting that in addition to thickness, the electrodes area is also a parameter. The negative resistance often observed in conductivity measurements is also discussed. The fact that C-C bonds are more easily broken than expected implies that this phenomenon must be looked at more carefully. The role of the free radicals thus created requires more attention. It is suggested that the interpretation of several measurements, mobility for example, might require some revision. Among other things, interpreting results using only an activation energy is not likely to give a correct description of the measured phenomenon since entropie effects are quite significant with most polymers. Finally, one may wonder if the usual explanation for some trapped sites in the so-called forbidden band of polyethylene still makes sense considering the fact that charge transport is mainly affected by the bonds broken by the applied stress.
2007 Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, 2007
ABSTRACT We show that our new aging concept describes the electrical aging process of XLPE and, i... more ABSTRACT We show that our new aging concept describes the electrical aging process of XLPE and, in fact applies to all polymers with free volume. The physical significance of the basic parameters (activation energy and volume) is discussed and it is shown that XLPE cable aging directly depends on the breaking of C-C bonds. The influence of samples size is briefly discussed as well as the influence of free radicals.
IEEE International Symposium on Electrical Insulation
ABSTRACT
1991 Annual Report. Conference on Electrical Insulation and Dielectric Phenomena,
ABSTRACT First Page of the Article
2000 Annual Report Conference on Electrical Insulation and Dielectric Phenomena (Cat. No.00CH37132)
ABSTRACT Water treeing depends on many parameters, especially frequency. We have reviewed the lit... more ABSTRACT Water treeing depends on many parameters, especially frequency. We have reviewed the literature for water trees grown in polyethylene soaked at room temperature in distilled water and various NaCl solutions. All existing data obtained with water needle electrodes (Ascraft cells) obey one single relationship between water-tree length and the number of field cycles, i.e. the frequency×time. The upper frequency limit of this process appears to be in the 30 kHz range. The effect of ion concentration is more influential for a large number of field cycles (above 108 cycles), but is not as significant as the frequency effect. The field calculated at water needle defect, ranging from 80 to 600 kV/mm, has little influence on water tree length. The practical impact of these observations is briefly discussed