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Automatik för avstämning av Petersenspole

Jönsson, Andreas and Örndal, Christoffer (2009) In LUTEDX/TEIE EIE920 20092
Industrial Electrical Engineering and Automation
Abstract
The forceful storms and the stricter regulations from the government within the last years have forced E.ON to start a project called “Krafttag”. The goal of the project is to ensure uninterrupted power supply to the customers by investing in underground cables. A problem with the underground cables is the high natural capacitance that contributes to an enlarged current in the case of an earth fault. The increase will among other things make the earth fault detection more complicated.
To compensate for the capacitive fault current caused by the cables, a coil in the neutral point of the transformer could be installed. The coil creates an inductive current that if correctly tuned will balance out the capacitive fault current. In systems... (More)
The forceful storms and the stricter regulations from the government within the last years have forced E.ON to start a project called “Krafttag”. The goal of the project is to ensure uninterrupted power supply to the customers by investing in underground cables. A problem with the underground cables is the high natural capacitance that contributes to an enlarged current in the case of an earth fault. The increase will among other things make the earth fault detection more complicated.
To compensate for the capacitive fault current caused by the cables, a coil in the neutral point of the transformer could be installed. The coil creates an inductive current that if correctly tuned will balance out the capacitive fault current. In systems with mostly overhead lines a change of the net will have a minor effect on the needed compensation and tuning is less critical. But with underground cables this is no longer the case, this introduces demands on systems that could tune the coils inductance quickly and effectively.
This master thesis focuses on evaluating the different methods for automatic tuning that are available on the market today and evaluate how they can be improved. Those improvements are then implemented, and a new method is created. The different methods are evaluated in DLAB, a lab model of a 10 kV distribution net. Tests have been performed on four different net sizes in both symmetrical and unsymmetrical conditions.
The evaluation focus on how well the different methods tune the system and how essential input parameters should be set. The two main parameters evaluated are trig level and detuning.
The result shows that all the evaluated methods works but have room for improvements in both speed and precision. The tests also confirm some of the problems that E.ON encountered when setting the trig level. (Less)
Please use this url to cite or link to this publication:
author
Jönsson, Andreas and Örndal, Christoffer
supervisor
organization
course
EIE920 20092
year
type
H2 - Master's Degree (Two Years)
subject
publication/series
LUTEDX/TEIE
report number
5264
language
Swedish
id
1554157
alternative location
http://www.iea.lth.se/publications/MS-Theses/Full%20document/5264_full_document.pdf
date added to LUP
2013-01-23 13:22:09
date last changed
2014-09-04 08:30:16
@misc{1554157,
  abstract     = {The forceful storms and the stricter regulations from the government within the last years have forced E.ON to start a project called “Krafttag”. The goal of the project is to ensure uninterrupted power supply to the customers by investing in underground cables. A problem with the underground cables is the high natural capacitance that contributes to an enlarged current in the case of an earth fault. The increase will among other things make the earth fault detection more complicated.
To compensate for the capacitive fault current caused by the cables, a coil in the neutral point of the transformer could be installed. The coil creates an inductive current that if correctly tuned will balance out the capacitive fault current. In systems with mostly overhead lines a change of the net will have a minor effect on the needed compensation and tuning is less critical. But with underground cables this is no longer the case, this introduces demands on systems that could tune the coils inductance quickly and effectively.
This master thesis focuses on evaluating the different methods for automatic tuning that are available on the market today and evaluate how they can be improved. Those improvements are then implemented, and a new method is created. The different methods are evaluated in DLAB, a lab model of a 10 kV distribution net. Tests have been performed on four different net sizes in both symmetrical and unsymmetrical conditions.
The evaluation focus on how well the different methods tune the system and how essential input parameters should be set. The two main parameters evaluated are trig level and detuning.
The result shows that all the evaluated methods works but have room for improvements in both speed and precision. The tests also confirm some of the problems that E.ON encountered when setting the trig level.},
  author       = {Jönsson, Andreas and Örndal, Christoffer},
  language     = {swe},
  note         = {Student Paper},
  series       = {LUTEDX/TEIE},
  title        = {Automatik för avstämning av Petersenspole},
  year         = {2009},
}