Erik Winkelmann | Technische Universität Dresden (original) (raw)
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Papers by Erik Winkelmann
VDE Hochspannungsfachtagung, 2020
The partial discharge measurement according to IEC 60270 is a widely used method for evaluating t... more The partial discharge measurement according to IEC 60270 is a widely used method for evaluating the quality of an insulation arrangement. The determined QIEC value also serves as a commercial criterion for assessing the quality of equipment and components and is therefore an essential part of factory acceptance tests. Exceeding contractually agreed QIEC values can lead to commercial consequences. The IEC 60270 standard describes various concepts for the design of partial discharge measuring devices. Within these concepts, further degrees of freedom are given for the measuring circuit and the evaluation of the measured data. This paper is investigating the influence of the permitted parameters on the QIEC value determined according to IEC 60270. A concentrated test setup that allows to test different measuring systems simultaneously was used to examine different setups and the resulting QIEC values. The analysis of this data showed that the QIEC values can be influenced through targeted parameter variations within the permitted ranges according to IEC 60270. Finally, proposals were derived to improve the reproducibility of the determined QIEC values. These proposals should initiate a technical multilateral discussion on how partial discharge measurement technologies should be developed further, based on modern and highly improved digital instruments and evaluations.
CEIDP, 2021
The presented research lies in the field of partial discharge (PD) signal acquisition for testing... more The presented research lies in the field of partial
discharge (PD) signal acquisition for testing and monitoring of
high voltage AC and DC cable systems. A high frequency current
transformer (HFCT) is a well-known device for coupling of PD
signals at electrical equipment. In high voltage cable systems, the
coupling is often carried out at shields of joints and terminations.
The use of this position has the benefit of absence of rated
current. However, this approach leads to a locally sensitive PD
detection, resulting in the requirement to measure every critical
component (e.g. every joint and termination). Coupling to PD
signals in the cable core might be more effective as it allows a
high global sensitivity. This is essential in respect of the ongoing
rapid development of the long cable corridor projects. Available
on the market HFCTs cannot be used for coupling to the cable
core due to the low saturation currents and small apertures.
In this paper, at first, the grid compatibility requirements for a
cable-core-coupled HFCT were defined. According to them, the
development and experimental validation of the prototype was
performed. Particularly, the influence on the grid and the ability
to withstand stationary as well as dynamic operating conditions
while maintaining sufficient performance were investigated.
ETG Congress, 2021
The current state of the art for localizing defects in cable systems includes synchronous, multi-... more The current state of the art for localizing defects in cable systems includes synchronous, multi-channel signal propagation time measurements and the use of time or frequency domain reflectometry. The length of the cable system to be diagnosed limits these technologies. A wave propagating as a result of a dielectric defect is attenuated due to the properties of the transmission path and deformed due to dispersion. The attenuation makes it difficult to detect the signal depending on the background noise level present during the measurement and the distance between the point of origin and the point of measurement. Disadvantages of the current technologies are the high economic and technical effort and the lack of adaptability. Here, a novel approach for a highly sensitive localization of defects in cable systems based on an adaptive cable model is presented. The location of the fault can be determined using the information obtained from the measured signal. First measurements to validate this procedure were carried out and the functionality of the described approach was proven with a minimum localization error of less than 2%. The advantages and disadvantages of the presented approach and its sensitivity are discussed. The sensitivity of the used coupling device allows the detection of a 20 pC pulse injected 6.6 km away.
CIRED, 2021
Maximizing the utilization of grid components in operation is a major challenge for distribution ... more Maximizing the utilization of grid components in operation is a major challenge for distribution system operators. In order to achieve this, assessment of the technical conditions of the equipment is required. The dielectric performance of insulation systems can be evaluated by the interpretation of Partial Discharge (PD) signals. Evaluation of the characteristics of these time-resolved signals is of highest importance. Conventional methods have several drawbacks, such as the complexity of the test setup and the settings as well as costs of the systems. Available PD measuring systems are not designed to face future challenges arising from Direct Current (DC)-infrastructure for energy distribution. To apply machine learning (ML) algorithms, typically the complete time signals have to be provided in order to extract features. In the present study, to allow a real-time processing at high signal resolutions, an automatically initializing algorithm was developed to separate noise and deterministic signals from each other. The PD or interference signals are available for extended signal processing such as clustering or classification. The implementation of this technology for Alternating Current (AC) and DC voltage applications was evaluated under practical conditions. Finally, an outlook on future applications and options using algorithms of ML in combination with the presented technology is given.
IEEE Electrical Insulation Magazine
Lecture Notes in Electrical Engineering
In this contribution, a new separation method for partial discharge signals and disturbances is i... more In this contribution, a new separation method for partial discharge signals and disturbances is introduced. In contrast to frequency rejection filter techniques like low or high-pass filters as de-noising methods, a correlation filter is used to separate the acquired signals into different signal classes. For that, a test circuit for the measurement of partial discharge signals under dc voltage was set up. Two test samples for the generation of corona and surface discharges as typical partial discharge sources were used to obtain test signals for the presented classification algorithm. Besides partial discharge signals, additional disturbances from the power supply, which was realized by the application of a half-wave rectifier, were also measured. Spectral analyses of the measured signals show the difficulties when using common frequency-rejection filter methods since the relevant spectral contents of discharge signals and disturbances are located in the same frequency range. An application of these filter methods for de-noising would influence the waveform of the partial discharge signals and impede further analyses due to a limitation respectively a loss of their relevant spectral contents. The new approach provides a separation method for different signals without an influence on the pulse shape by using a correlation filter method. Histogram analyses of the correlation coefficients show a clear differentiation of the signal classes and present thresholds for the distinction between correlated and uncorrelated events. The consistence of each single signal class is proven to ensure a high similarity of the events obtained from the same test sample. The correlation between two signal classes lead to coefficients below the determined threshold value, which indicates a comparison of events from different classes. In a last experiment, the results from the histogram analysis were implemented in a classification algorithm to separate the raw data into specific classes and presents a new approach for the grouping of unknown signals in comparison to multi-channel processing tools like the 3 Center Frequency Relation Diagram (3CFRD).
Die Erfindung betrifft Verfahren zur reproduzierbaren Aromatisierung von einzelnen Genusseinheite... more Die Erfindung betrifft Verfahren zur reproduzierbaren Aromatisierung von einzelnen Genusseinheiten von Bier in einer Bierzapfanlage, bei dem a) ein mit einer auf die Menge einer oder mehrerer Genusseinheiten abgestimmten Menge an festem Aromatrager gefullter und mit Bier durchstrombarer Behalter in eine in der Bierzapfanlage integrierte, mit mindestens einem Bierzulauf und Bierablauf verbundene Hopfenkammer eingesetzt wird, wobei beim Einsetzen des Behalters der Bierzulauf in die Hopfenkammer gesperrt ist, b) der eingesetzte Behalter in der Hopfenkammer derart befestigt und nach ausen hin derart abgedichtet wird, dass ein Stromungsweg des Biers, der vom Bierzulauf durch den mit dem Aromatrager gefullten Behalter in den Bierablauf fuhrt, bereitgestellt wird, c) der Bierzulauf geoffnet wird, so dass uber den Bierzulauf, mit einem Eingangsdruck von mindestens 0,1 bar in die Hopfenkammer und somit in den mit dem Aromatrager gefullten Behalter stromt und durch Extraktion von lipophilen A...
VDE Hochspannungsfachtagung, 2020
The partial discharge measurement according to IEC 60270 is a widely used method for evaluating t... more The partial discharge measurement according to IEC 60270 is a widely used method for evaluating the quality of an insulation arrangement. The determined QIEC value also serves as a commercial criterion for assessing the quality of equipment and components and is therefore an essential part of factory acceptance tests. Exceeding contractually agreed QIEC values can lead to commercial consequences. The IEC 60270 standard describes various concepts for the design of partial discharge measuring devices. Within these concepts, further degrees of freedom are given for the measuring circuit and the evaluation of the measured data. This paper is investigating the influence of the permitted parameters on the QIEC value determined according to IEC 60270. A concentrated test setup that allows to test different measuring systems simultaneously was used to examine different setups and the resulting QIEC values. The analysis of this data showed that the QIEC values can be influenced through targeted parameter variations within the permitted ranges according to IEC 60270. Finally, proposals were derived to improve the reproducibility of the determined QIEC values. These proposals should initiate a technical multilateral discussion on how partial discharge measurement technologies should be developed further, based on modern and highly improved digital instruments and evaluations.
CEIDP, 2021
The presented research lies in the field of partial discharge (PD) signal acquisition for testing... more The presented research lies in the field of partial
discharge (PD) signal acquisition for testing and monitoring of
high voltage AC and DC cable systems. A high frequency current
transformer (HFCT) is a well-known device for coupling of PD
signals at electrical equipment. In high voltage cable systems, the
coupling is often carried out at shields of joints and terminations.
The use of this position has the benefit of absence of rated
current. However, this approach leads to a locally sensitive PD
detection, resulting in the requirement to measure every critical
component (e.g. every joint and termination). Coupling to PD
signals in the cable core might be more effective as it allows a
high global sensitivity. This is essential in respect of the ongoing
rapid development of the long cable corridor projects. Available
on the market HFCTs cannot be used for coupling to the cable
core due to the low saturation currents and small apertures.
In this paper, at first, the grid compatibility requirements for a
cable-core-coupled HFCT were defined. According to them, the
development and experimental validation of the prototype was
performed. Particularly, the influence on the grid and the ability
to withstand stationary as well as dynamic operating conditions
while maintaining sufficient performance were investigated.
ETG Congress, 2021
The current state of the art for localizing defects in cable systems includes synchronous, multi-... more The current state of the art for localizing defects in cable systems includes synchronous, multi-channel signal propagation time measurements and the use of time or frequency domain reflectometry. The length of the cable system to be diagnosed limits these technologies. A wave propagating as a result of a dielectric defect is attenuated due to the properties of the transmission path and deformed due to dispersion. The attenuation makes it difficult to detect the signal depending on the background noise level present during the measurement and the distance between the point of origin and the point of measurement. Disadvantages of the current technologies are the high economic and technical effort and the lack of adaptability. Here, a novel approach for a highly sensitive localization of defects in cable systems based on an adaptive cable model is presented. The location of the fault can be determined using the information obtained from the measured signal. First measurements to validate this procedure were carried out and the functionality of the described approach was proven with a minimum localization error of less than 2%. The advantages and disadvantages of the presented approach and its sensitivity are discussed. The sensitivity of the used coupling device allows the detection of a 20 pC pulse injected 6.6 km away.
CIRED, 2021
Maximizing the utilization of grid components in operation is a major challenge for distribution ... more Maximizing the utilization of grid components in operation is a major challenge for distribution system operators. In order to achieve this, assessment of the technical conditions of the equipment is required. The dielectric performance of insulation systems can be evaluated by the interpretation of Partial Discharge (PD) signals. Evaluation of the characteristics of these time-resolved signals is of highest importance. Conventional methods have several drawbacks, such as the complexity of the test setup and the settings as well as costs of the systems. Available PD measuring systems are not designed to face future challenges arising from Direct Current (DC)-infrastructure for energy distribution. To apply machine learning (ML) algorithms, typically the complete time signals have to be provided in order to extract features. In the present study, to allow a real-time processing at high signal resolutions, an automatically initializing algorithm was developed to separate noise and deterministic signals from each other. The PD or interference signals are available for extended signal processing such as clustering or classification. The implementation of this technology for Alternating Current (AC) and DC voltage applications was evaluated under practical conditions. Finally, an outlook on future applications and options using algorithms of ML in combination with the presented technology is given.
IEEE Electrical Insulation Magazine
Lecture Notes in Electrical Engineering
In this contribution, a new separation method for partial discharge signals and disturbances is i... more In this contribution, a new separation method for partial discharge signals and disturbances is introduced. In contrast to frequency rejection filter techniques like low or high-pass filters as de-noising methods, a correlation filter is used to separate the acquired signals into different signal classes. For that, a test circuit for the measurement of partial discharge signals under dc voltage was set up. Two test samples for the generation of corona and surface discharges as typical partial discharge sources were used to obtain test signals for the presented classification algorithm. Besides partial discharge signals, additional disturbances from the power supply, which was realized by the application of a half-wave rectifier, were also measured. Spectral analyses of the measured signals show the difficulties when using common frequency-rejection filter methods since the relevant spectral contents of discharge signals and disturbances are located in the same frequency range. An application of these filter methods for de-noising would influence the waveform of the partial discharge signals and impede further analyses due to a limitation respectively a loss of their relevant spectral contents. The new approach provides a separation method for different signals without an influence on the pulse shape by using a correlation filter method. Histogram analyses of the correlation coefficients show a clear differentiation of the signal classes and present thresholds for the distinction between correlated and uncorrelated events. The consistence of each single signal class is proven to ensure a high similarity of the events obtained from the same test sample. The correlation between two signal classes lead to coefficients below the determined threshold value, which indicates a comparison of events from different classes. In a last experiment, the results from the histogram analysis were implemented in a classification algorithm to separate the raw data into specific classes and presents a new approach for the grouping of unknown signals in comparison to multi-channel processing tools like the 3 Center Frequency Relation Diagram (3CFRD).
Die Erfindung betrifft Verfahren zur reproduzierbaren Aromatisierung von einzelnen Genusseinheite... more Die Erfindung betrifft Verfahren zur reproduzierbaren Aromatisierung von einzelnen Genusseinheiten von Bier in einer Bierzapfanlage, bei dem a) ein mit einer auf die Menge einer oder mehrerer Genusseinheiten abgestimmten Menge an festem Aromatrager gefullter und mit Bier durchstrombarer Behalter in eine in der Bierzapfanlage integrierte, mit mindestens einem Bierzulauf und Bierablauf verbundene Hopfenkammer eingesetzt wird, wobei beim Einsetzen des Behalters der Bierzulauf in die Hopfenkammer gesperrt ist, b) der eingesetzte Behalter in der Hopfenkammer derart befestigt und nach ausen hin derart abgedichtet wird, dass ein Stromungsweg des Biers, der vom Bierzulauf durch den mit dem Aromatrager gefullten Behalter in den Bierablauf fuhrt, bereitgestellt wird, c) der Bierzulauf geoffnet wird, so dass uber den Bierzulauf, mit einem Eingangsdruck von mindestens 0,1 bar in die Hopfenkammer und somit in den mit dem Aromatrager gefullten Behalter stromt und durch Extraktion von lipophilen A...