Constantin Balzer

Constantin Balzer M.Sc.

+49 6151 16-20436
+49 6151 16-20434

Fraunhoferstr. 4
64283 Darmstadt

Office: S3|21 402

Teaching

Overvoltage Protection and Isolation Coordination

Project description

Drying out of soil around a MV-cable (trefoil-configuration) at the cable test site of TU Darmstadt
Drying out of soil around a MV-cable (trefoil-configuration) at the cable test site of TU Darmstadt

In case of transmission of electrical energy by buried cables, the electrical losses will be dissi-pated to the environment in the form of heat. This leads to an increase of temperature of the conductor of the cable. As the latter is limited and directly proportional to the current, the so called thermal current rating represents one important limit of the cable capacity.

At present, the cable ampacity ratings are estab-lished based on standardized consumption patterns and conservative assumptions regarding the thermal properties of the bedding. Thereby, values below the actual limit are derived. This is particularly relevant for a high daily and seasonal dynamic in load patterns that is typical for power injection from photovoltaic generation. Moreover, the influence of natural water content changes of the surrounding soil on the thermal properties of the bedding is not taken into consideration.

The research project comprises primarily three distinct aspects: laboratory-based analyses under predefined boundary conditions; measurements under realistic conditions in a therefore built cable test site, and modelling the results using numerical simulations.

The results will finally be implemented into an online monitoring tool that provides the system operator with real time ampacity ratings that have been calculated with the help of measured or estimated data.

Laboratory Experiments

Laboratory experiment for investigations on changes of the properties of bedding material around a horizontal line heat source
Laboratory experiment for investigations on changes of the properties of bedding material around a horizontal line heat source

In order to quantify the thermophysical, hydraulic and geotechnical properties of soils and bedding materials, an evaporation test was modified among others to measure all relevant thermophysical and hydraulic properties of a sample simultaneously in comparatively short time.

To assess the dependency of these properties on the degree of compaction as well as the influence of the latent and convectional heat transport on the effec-tive heat conductivity, a special measurement device was developed and patented

Moreover, a true to scale experimental configura-tion was set up with the purpose of recreating the drying out of soil in the vicinity of the cable that has a significant negative impact on the ampacity rating.

Real-Scale Field Experiment Cable Test Site

Aerial photograph of the test site – 2015
Aerial photograph of the test site – 2015

In order to quantify the implact of environmental conditions, a large field experiment was built at TU Darmstadt in 2013. This experimental set-up ena-bles for investigations on various cables and cable arrangement in different bedding materials and soils under natural conditions. The overall dimen-sion of the test site is 14 m by 6 m, divided into four sections of 3.5 m length that are hydraulically and thermally decoupled by each other. The changes of the thermal and hydraulic condi-tions within the test site are monitored by numerous sensors.

Numeric Modelling

Example of the modelling of convection inside a protection pipe. The streaming velocity in m s-1 is shown for two different cable positions
Example of the modelling of convection inside a protection pipe. The streaming velocity in m s-1 is shown for two different cable positions

The data that is collected by the laboratory experiments and the cable test side are finally used to validate numeric models. They implement all relevant physical processes and allow conducting parameter variations of all kind in order to derive general conclusions that may afterwards be implemented in the grid operation.

Publications

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Gruppiere nach: Publikationsjahr | Typ des Eintrags | Keine Gruppierung
Springe zu: 2018 | 2017 | 2016 | 2015
Anzahl der Einträge: 14.

2018

Rusek, B. ; Steevens, S. ; Kleinekorte, K. ; Hannig, M. ; Balzer, C. ; Hinrichsen, V. ; Neumann, C. (2018):
Dimensioning of Electrical Clearance of OHL Using Correlation between Weather Condition and Lightning Strike Probability.
In: Cigre Session 2018, Paris, 27.8.2018 - 30.8.2018, [Konferenzveröffentlichung]

Rusek, B. ; Steevens, S. ; Kleinekorte, K. ; Hannig, M. ; Balzer, C. ; Hinrichsen, V. ; Neumann, C. (2018):
Dimensioning of Electrical Clearance of OHL Using Correlation between Weather Condition and Lightning Strike Probability.
In: Cigré Session 2018, Paris, 26.08.2018 - 31.08.2018, [Konferenzveröffentlichung]

Drefke, C. ; Schedel, M. ; Balzer, C. ; Hinrichsen, V. ; Sass, I. (2018):
Kombinierter Wärme- und Stofftransport um erdverlegte Energiekabel - Potenziale einer optimierten Bettung auf die thermische Stromtragfähigkeit.
In: Zukünftige Stromnetze für erneuerbare Energien, Berlin, 30.01.-31.01.2018, [Konferenzveröffentlichung]

2017

Balzer, C. ; Drefke, C. ; Schedel, M. ; Hinrichsen, V. ; Sass, I. (2017):
Quantifizierung des Einflusses von Umweltbedingungen und boden-physikalischen Eigenschaften der Bettung auf die thermische Strom-tragfähigkeit von Mittelspannungs-Energiekabelsystemen.
In: International ETG Congress 2017, Bonn, 28-28 November, [Konferenzveröffentlichung]

Balzer, C. ; Drefke, C. ; Schedel, M. ; Hinrichsen, V. ; Sass, I. (2017):
Analytical calculation of the thermal impedance of soil under various boundary conditions to enhance current ratings of buried power transmission and distribution cable systems.
[Konferenzveröffentlichung]

Schedel, M. ; Drefke, C. ; Balzer, C. ; Hinrichsen, V. ; Sass, I. Deutsche Gesellschaft für Geotechnik e.V., (DGGT) (Hrsg.) (2017):
Einflussfaktoren auf die Wärme- und Massetransportprozesse um erdverlegte Stromkabel.
In: Tagungsband der Fachsektionstage Geotechnik – Interdisziplinäres Forum 2017, S. 216-221, [Buchkapitel]

Drefke, C. ; Schedel, M. ; Stegner, J. ; Balzer, C. ; Hinrichsen, V. ; Sass, I. (2017):
Measurement Method of Thermal Properties of Cementitious Bedding Materials and Unsaturated Soils: Hydraulic Influence on Thermal Parameters.
40, In: Geotechnical Testing Journal, (1), S. 160-170, ISSN 01496115, [Online-Edition: http://dx.doi.org/10.1520/GTJ20160027],
[Artikel]

2016

Balzer, C. ; Hinrichsen, Volker ; Rusek, B. (2016):
Statistische Bestimmung von Überspannungen bei Einschaltvorgängen von Freileitungen zur Dimensionierung von Isolatorketten.
In: VDE-Fachtagung Hochspannungstechnik 2016, Berlin, 14.-16. November 2016, [Konferenzveröffentlichung]

Drefke, C. ; Schedel, M. ; Balzer, C. ; Hinrichsen, V. ; Sass, I. (2016):
Experimentelle Bestimmung der Dynamik von Bodenaustrocknung und der Wiederherstellung der Bodenfeuchte um Energiekabel.
In: VDE-Hochspannungstechnik 2016, Berlin, 14.-16.11.2016, [Konferenzveröffentlichung]

Drefke, C. ; Schedel, M. ; Stegner, J. ; Balzer, C. ; Sass, I. ; Hinrichsen, V. (2016):
Einfluss der hydraulischen Eigenschaften von Bettungsmaterialien auf die Belastbarkeit erdverlegter Stromkabel.
In: 25. Tagung der Fachsektion Hydrogeologie in der DGGV 2016, Karlsruher Institut für Technologie (KIT), 13.–17. April 2016, [Konferenzveröffentlichung]

2015

Schedel, M. ; Drefke, C. ; Stegner, J. ; Balzer, C. ; Hinrichsen, V. ; Sass, I. (2015):
Veränderung der thermophysikalischen Eigenschaften von Materialien zur Bettung erdverlegter Stromkabel bei instationären Wassergehalten in teilgesättigten Lockergesteinen.
In: Der Geothermiekongress 2015, Essen, 02.-04.11.2015, [Konferenzveröffentlichung]

Drefke, C. ; Dietrich, J. ; Stegner, J. ; Balzer, C. ; Hinrichsen, V. ; Sass, I. (2015):
Steigerung der thermischen Stromtragfähigkeit von Kabel-Hüllrohrsystemen.
Jahrgang 54, In: Netzpraxis, (11), EW Medien und Kongresse GmbH, S. 28-34, ISSN 1611-0412, [Artikel]

Balzer, C. ; Drefke, C. ; Stegner, J. ; Hinrichsen, V. ; Sass, I. ; Hentschel, K. ; Dietrich, J. Technische Universität Darmstadt, Fachgebiet Hochspannungstechnik, Technische Universität Darmstadt, Fachgebiet Angewandte Geothermie (Urheber) (2015):
Improvement of Ampacity Ratings of Medium Voltage Cables in Protection Pipes by Comprehensive Consideration and Selective Improvement of the Heat Transfer Mechanisms within the Pipe.
In: 9th International Conference on Insulated Power Cables - Jicable 2015, Versailles, Frankreich, 22.-24.06.2015, [Konferenzveröffentlichung]

Balzer, C. ; Drefke, C. ; Stegner, J. ; Hinrichsen, V. ; Sass, I. ; Hentschel, K. ; Dietrich, J. Technische Universität Darmstadt, Fachgebiet Hochspannungstechnik, Technische Universität Darmstadt, Fachgebiet Angewandte Geothermie (Urheber) (2015):
Ampacity Rating of Directly Buried Distribution Cables under the Consideration of Soil Properties to Improve Efficiency of Distribution Networks.
In: 23rd International Conference on Electricity Distribution - CIRED 2015, Lyon, Frankreich, 15.-18.06.2015, [Konferenzveröffentlichung]

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