Nowadays there are several transmission lines projected to be operating in high-altitude regions.... more Nowadays there are several transmission lines projected to be operating in high-altitude regions. It is well known that the installation altitude has an impact on the dielectric behavior of air-insulated systems. As a result, atmospheric and voltage correction factors must be applied in air-insulated transmission systems operating in high-altitude conditions. This paper performs an exhaustive literature review, including state-of-the-art research papers and International Standards of the available correction factors to limit corona activity and ensure proper performance when planning air-insulated transmission lines intended for high-altitude areas. It has been found that there are substantial differences among the various correction methods, differences that are more evident at higher altitudes. Most high-voltage standards were not conceived to test samples to be installed in high-altitude regions and, therefore, most high-voltage laboratories are not ready to face this issue, sinc...
ABSTRACT HVDC energy transmission is crucial for a successful uptake of renewable energy sources ... more ABSTRACT HVDC energy transmission is crucial for a successful uptake of renewable energy sources in the grid. A research program is described, intended to provide metrology support for the needs of HVDC energy transmission. This program will provide improvements for the present HVDC metrology infrastructure: accurate measurement of HVDC, determination of losses in HVDC systems, on-site power quality measurements at HVDC substations, and DC metering. It is a combined effort of 7 European national metrology institutes, one university and one industrial partner.
2003 IEEE Bologna Power Tech Conference Proceedings,, 2003
A new method of transfer function analysis using spectral density estimates in conjunction with a... more A new method of transfer function analysis using spectral density estimates in conjunction with a random error and coherence function calculation has shown excellent experimental results in identifying mechanical displacements in the windings of power transformers. The new technique represents an extension of the traditional low voltage impulse method of frequency response analysis (FRA). Traditional low voltage impulse methods have
rent standard IEC 60270, WG D1.33 “High-Voltage Testing and Measuring Techniques” decided the edi... more rent standard IEC 60270, WG D1.33 “High-Voltage Testing and Measuring Techniques” decided the edition of a Technical Brochure, which is intended as a guideline for engineers dealing with conventional electrical PD measurements. In this context it should be noted that currently the new standard IEC 62478 is under preparation, which covers non-conventional electromagnetic and acoustical PD detection methods. These topics, however, are outside of the scope of this brochure.
A new technique, termed Objective Winding Asymmetry (OWA), has demonstrated the ability to detect... more A new technique, termed Objective Winding Asymmetry (OWA), has demonstrated the ability to detect winding displacements in three phase high voltage transformers through an enhanced method of transfer function analysis, obtained via nondestructive low voltage impulse measurements. Traditional frequency response analysis (FRA) techniques have been limited in their application to the comparison of transfer function fingerprints obtained at different times or from identical units. A new method of estimating the transfer function has been developed that uses Spectral Density Estimate building blocks. Transfer function estimates are calculated using specially developed weighting and averaging techniques applied in the frequency domain, following the application of a series of ten impulse measurements per winding configuration. The final transfer function estimates are then compared across phases, and the OWA is calculated for windings showing the greatest asymmetry. Based on typical phase...
Recently, IEC and IEEE have published a number of revised and new standards for high-voltage and ... more Recently, IEC and IEEE have published a number of revised and new standards for high-voltage and high-current testing. Significant changes and additions have been introduced to these revised and ne ...
Recently, IEC and IEEE have published a number of revised and new standards for high-voltage and ... more Recently, IEC and IEEE have published a number of revised and new standards for high-voltage and high-current testing. Significant changes and additions have been introduced to these revised and ne ...
On-site testing has often been requested by the utilities following installation of new HV cables... more On-site testing has often been requested by the utilities following installation of new HV cables and also to check the condition of HV power transformers suspected of a damaged insulation. Specialized equipment for on-site tests has to withstand off-road transportation, to pass under road-bridges, be equipped with its own power source, and what is most difficult, to make measurements at HV substations which are notorious for intense electromagnetic interference. At present a HV resonant test set-up with the partial discharge (PD) measuring instrument and the C-tgδ bridge with built-in test voltage source are the most frequently used mobile test equipment. This paper presents a mobile HV resonant test set-up for installed cable testing and measuring instruments designed for on-site transformer insulation testing
Page 1. 5.232.P5 On-Site Testing of Gas Insulated Substation with AC voltage M. Gnmlin, J. Rickni... more Page 1. 5.232.P5 On-Site Testing of Gas Insulated Substation with AC voltage M. Gnmlin, J. Rickniann, P. Scliikarski ... ii 1 . IL-~i~ j~~ -4 0 5 1 15 2 8% 0 5 1 1 5 frequency In GW frequency In GHZ Figure 8: lJHFsiynals iiieosrrred of sensor 3 /el): pee niuving parlicle, SpC. ...
2012 IEEE International Symposium on Electrical Insulation, 2012
The use of insulated medium and high voltage cables for the transmission of AC power over longer ... more The use of insulated medium and high voltage cables for the transmission of AC power over longer and longer distances has presented serious challenges to the conventional methods and equipment utilized to perform final tests on laid cables prior to grid energization. EHV cable circuits are now commonly ranging up to some tens of kilometers in length, resulting in very large capacitive charging currents when energized up to the AC test voltage levels specified in IEEE and IEC standards. A number of competitive testing technologies have arisen in recent years, such as Very Low Frequency (VLF) AC testing and Damped Alternating Voltages (DAV) which when combined with a partial discharge measurement all claim to be able to locate defects in the cable and its accessories. Although such testing technologies may appear to offer some relative advantages in terms of reduced weight and dimensions (improved transportability) and lower initial equipment cost, there continues to be controversy throughout the industry as to the effectiveness of these techniques in detecting defects. Indeed, in the case of the VLF technique, serious questions persist as to whether or not this method may actually be inflicting damage to the cable. It is for this reason that High Voltage AC testing, either with or without a simultaneous partial discharge measurement, remains the preferred test method. Modern insulated gate bipolar transistors (IGBT) may be used to construct relatively low cost, simple and robust frequency converters capable of supplying power in the range of some hundreds of kVA. The AC response of a resonant circuit comprised of inductive and capacitive energy storage elements is governed by the quality factor of the circuit, or the ratio of reactive power to real power. Since the high voltage cable appears to the source as a nearly purely capacitive load in the frequency range of interest, the quality factor of the test circuit can be quite high. It is not uncommon in such circuits to achieve quality factors as high as 200. When combined with an IGBT based frequency converter capable of supplying a variable frequency AC excitation source rated up to several hundreds of kVA, an effective AC testing power in the range of tens of MVA is achievable. In conclusion, the first part of this paper reviews research results on the comparison of different voltage sources and frequencies with regard to 50-60 Hz testing. The second part is an overview of the extremely high power resonance test system capabilities. Variable frequency resonance test systems utilize modern IGBT based frequency converters as the excitation source in a controlled high voltage resonant circuit whose capacitance component is comprised of the cable under test. Techniques for properly calculating the resonant frequency, the required testing power capacity and the resulting sizing of the frequency converter are covered in detail.
2001 IEEE/PES Transmission and Distribution Conference and Exposition. Developing New Perspectives (Cat. No.01CH37294), 2001
Ross Daharsh John Kise Terry McComb Ernst Hanique Jeffrey Britton Arthur Molden Barry Holst Larry... more Ross Daharsh John Kise Terry McComb Ernst Hanique Jeffrey Britton Arthur Molden Barry Holst Larry Coffeen Nigel McQuin Dave Nichols Dana Dufield Randy Newnam Herman Schneider Gerald Fitzpatrick Gary Schneider Stephen Sebo Jeff Hildreth Dan Schweickart ...
ABSTRACT HVDC energy transmission is crucial for a successful uptake of renewable energy sources ... more ABSTRACT HVDC energy transmission is crucial for a successful uptake of renewable energy sources in the grid. A research program is described, intended to provide metrology support for the needs of HVDC energy transmission. This program will provide improvements for the present HVDC metrology infrastructure: accurate measurement of HVDC, determination of losses in HVDC systems, on-site power quality measurements at HVDC substations, and DC metering. It is a combined effort of 7 European national metrology institutes, one university and one industrial partner.
Nowadays there are several transmission lines projected to be operating in high-altitude regions.... more Nowadays there are several transmission lines projected to be operating in high-altitude regions. It is well known that the installation altitude has an impact on the dielectric behavior of air-insulated systems. As a result, atmospheric and voltage correction factors must be applied in air-insulated transmission systems operating in high-altitude conditions. This paper performs an exhaustive literature review, including state-of-the-art research papers and International Standards of the available correction factors to limit corona activity and ensure proper performance when planning air-insulated transmission lines intended for high-altitude areas. It has been found that there are substantial differences among the various correction methods, differences that are more evident at higher altitudes. Most high-voltage standards were not conceived to test samples to be installed in high-altitude regions and, therefore, most high-voltage laboratories are not ready to face this issue, sinc...
ABSTRACT HVDC energy transmission is crucial for a successful uptake of renewable energy sources ... more ABSTRACT HVDC energy transmission is crucial for a successful uptake of renewable energy sources in the grid. A research program is described, intended to provide metrology support for the needs of HVDC energy transmission. This program will provide improvements for the present HVDC metrology infrastructure: accurate measurement of HVDC, determination of losses in HVDC systems, on-site power quality measurements at HVDC substations, and DC metering. It is a combined effort of 7 European national metrology institutes, one university and one industrial partner.
2003 IEEE Bologna Power Tech Conference Proceedings,, 2003
A new method of transfer function analysis using spectral density estimates in conjunction with a... more A new method of transfer function analysis using spectral density estimates in conjunction with a random error and coherence function calculation has shown excellent experimental results in identifying mechanical displacements in the windings of power transformers. The new technique represents an extension of the traditional low voltage impulse method of frequency response analysis (FRA). Traditional low voltage impulse methods have
rent standard IEC 60270, WG D1.33 “High-Voltage Testing and Measuring Techniques” decided the edi... more rent standard IEC 60270, WG D1.33 “High-Voltage Testing and Measuring Techniques” decided the edition of a Technical Brochure, which is intended as a guideline for engineers dealing with conventional electrical PD measurements. In this context it should be noted that currently the new standard IEC 62478 is under preparation, which covers non-conventional electromagnetic and acoustical PD detection methods. These topics, however, are outside of the scope of this brochure.
A new technique, termed Objective Winding Asymmetry (OWA), has demonstrated the ability to detect... more A new technique, termed Objective Winding Asymmetry (OWA), has demonstrated the ability to detect winding displacements in three phase high voltage transformers through an enhanced method of transfer function analysis, obtained via nondestructive low voltage impulse measurements. Traditional frequency response analysis (FRA) techniques have been limited in their application to the comparison of transfer function fingerprints obtained at different times or from identical units. A new method of estimating the transfer function has been developed that uses Spectral Density Estimate building blocks. Transfer function estimates are calculated using specially developed weighting and averaging techniques applied in the frequency domain, following the application of a series of ten impulse measurements per winding configuration. The final transfer function estimates are then compared across phases, and the OWA is calculated for windings showing the greatest asymmetry. Based on typical phase...
Recently, IEC and IEEE have published a number of revised and new standards for high-voltage and ... more Recently, IEC and IEEE have published a number of revised and new standards for high-voltage and high-current testing. Significant changes and additions have been introduced to these revised and ne ...
Recently, IEC and IEEE have published a number of revised and new standards for high-voltage and ... more Recently, IEC and IEEE have published a number of revised and new standards for high-voltage and high-current testing. Significant changes and additions have been introduced to these revised and ne ...
On-site testing has often been requested by the utilities following installation of new HV cables... more On-site testing has often been requested by the utilities following installation of new HV cables and also to check the condition of HV power transformers suspected of a damaged insulation. Specialized equipment for on-site tests has to withstand off-road transportation, to pass under road-bridges, be equipped with its own power source, and what is most difficult, to make measurements at HV substations which are notorious for intense electromagnetic interference. At present a HV resonant test set-up with the partial discharge (PD) measuring instrument and the C-tgδ bridge with built-in test voltage source are the most frequently used mobile test equipment. This paper presents a mobile HV resonant test set-up for installed cable testing and measuring instruments designed for on-site transformer insulation testing
Page 1. 5.232.P5 On-Site Testing of Gas Insulated Substation with AC voltage M. Gnmlin, J. Rickni... more Page 1. 5.232.P5 On-Site Testing of Gas Insulated Substation with AC voltage M. Gnmlin, J. Rickniann, P. Scliikarski ... ii 1 . IL-~i~ j~~ -4 0 5 1 15 2 8% 0 5 1 1 5 frequency In GW frequency In GHZ Figure 8: lJHFsiynals iiieosrrred of sensor 3 /el): pee niuving parlicle, SpC. ...
2012 IEEE International Symposium on Electrical Insulation, 2012
The use of insulated medium and high voltage cables for the transmission of AC power over longer ... more The use of insulated medium and high voltage cables for the transmission of AC power over longer and longer distances has presented serious challenges to the conventional methods and equipment utilized to perform final tests on laid cables prior to grid energization. EHV cable circuits are now commonly ranging up to some tens of kilometers in length, resulting in very large capacitive charging currents when energized up to the AC test voltage levels specified in IEEE and IEC standards. A number of competitive testing technologies have arisen in recent years, such as Very Low Frequency (VLF) AC testing and Damped Alternating Voltages (DAV) which when combined with a partial discharge measurement all claim to be able to locate defects in the cable and its accessories. Although such testing technologies may appear to offer some relative advantages in terms of reduced weight and dimensions (improved transportability) and lower initial equipment cost, there continues to be controversy throughout the industry as to the effectiveness of these techniques in detecting defects. Indeed, in the case of the VLF technique, serious questions persist as to whether or not this method may actually be inflicting damage to the cable. It is for this reason that High Voltage AC testing, either with or without a simultaneous partial discharge measurement, remains the preferred test method. Modern insulated gate bipolar transistors (IGBT) may be used to construct relatively low cost, simple and robust frequency converters capable of supplying power in the range of some hundreds of kVA. The AC response of a resonant circuit comprised of inductive and capacitive energy storage elements is governed by the quality factor of the circuit, or the ratio of reactive power to real power. Since the high voltage cable appears to the source as a nearly purely capacitive load in the frequency range of interest, the quality factor of the test circuit can be quite high. It is not uncommon in such circuits to achieve quality factors as high as 200. When combined with an IGBT based frequency converter capable of supplying a variable frequency AC excitation source rated up to several hundreds of kVA, an effective AC testing power in the range of tens of MVA is achievable. In conclusion, the first part of this paper reviews research results on the comparison of different voltage sources and frequencies with regard to 50-60 Hz testing. The second part is an overview of the extremely high power resonance test system capabilities. Variable frequency resonance test systems utilize modern IGBT based frequency converters as the excitation source in a controlled high voltage resonant circuit whose capacitance component is comprised of the cable under test. Techniques for properly calculating the resonant frequency, the required testing power capacity and the resulting sizing of the frequency converter are covered in detail.
2001 IEEE/PES Transmission and Distribution Conference and Exposition. Developing New Perspectives (Cat. No.01CH37294), 2001
Ross Daharsh John Kise Terry McComb Ernst Hanique Jeffrey Britton Arthur Molden Barry Holst Larry... more Ross Daharsh John Kise Terry McComb Ernst Hanique Jeffrey Britton Arthur Molden Barry Holst Larry Coffeen Nigel McQuin Dave Nichols Dana Dufield Randy Newnam Herman Schneider Gerald Fitzpatrick Gary Schneider Stephen Sebo Jeff Hildreth Dan Schweickart ...
ABSTRACT HVDC energy transmission is crucial for a successful uptake of renewable energy sources ... more ABSTRACT HVDC energy transmission is crucial for a successful uptake of renewable energy sources in the grid. A research program is described, intended to provide metrology support for the needs of HVDC energy transmission. This program will provide improvements for the present HVDC metrology infrastructure: accurate measurement of HVDC, determination of losses in HVDC systems, on-site power quality measurements at HVDC substations, and DC metering. It is a combined effort of 7 European national metrology institutes, one university and one industrial partner.
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Papers by Johannes Rickmann