Vis enkel innførsel

dc.contributor.advisorMauseth, Frank
dc.contributor.advisorHalvorson, Hans Lavoll
dc.contributor.authorSøndenå, Peder Severin
dc.date.accessioned2018-08-23T14:01:33Z
dc.date.available2018-08-23T14:01:33Z
dc.date.created2018-06-21
dc.date.issued2018
dc.identifierntnudaim:18724
dc.identifier.urihttp://hdl.handle.net/11250/2559139
dc.description.abstractThe Norwegian power grid consists of an ever-increasing share of power cables. In Norway, the ground screen of the cable in distribution networks is usually grounded at each end of the cable length due to recommendations from the authorities. As a result, screen currents are allowed to flow through the ground screen due to the voltage induced in it by the current of the cable conductor and surrounding current carrying objects. The screen currents may vary from a few to several hundreds of amperes, depending on cable dimensions, load current and laying configurations. If this is not taken into consideration when designing the layout of the cable system, large screen currents may arise that can cause significant heating to occur in the cable screen and its connections. Several breakdowns of power cables have occurred in the distribution grid, which are believed to be connected to the above mentioned topics. Because of this, a research project was initiated by REN AS with the goal of "establishing guidelines for testing and installation of ground screen connections to avoid future fault scenarios and to increase the reliability of the cable network" [1], and further use this knowledge as a basis to propose international standardization tests for ground screen connections. The project has mainly been experimental, and focus has been to study the mechanisms of known fault scenarios in a typical ground screen connection. Two types of ground screen connection designs were obtained from Norwegian equipment vendors. A test setup was built allowing six ground screen connections of each type to be tested. The cable ground screens and the ground screen connections were heat cycled by a DC current source. In addition, the cable conductors were heated by inducing current from a ring transformer and a variable voltage source. 25 heat cycles were conducted with the ground screen connections installed as explained in the installation manuals, before the same number of heat cycles were performed with the known improper installation on the two designs. The resistance of the ground screen connections was monitored with four-point resistance measurement before, during and between the heat cycles. The results show that the improper installation of the ground screen connections increase the resistance drastically. With a screen current of 30 A, type I experienced a temperature increase close to that of the correct installation with 100 A. Type II saw an increased temperature with 30 A and improper installation compared to correct installation of the ground screen connection with 100 A. [1]: https://www.forskningsradet.no/prosjektbanken/#/project/NFR/256261
dc.languageeng
dc.publisherNTNU
dc.subjectEnergi og miljø, Elektriske anlegg
dc.titleReliable Power Cable Ground Screen Connections - Resistance of improper ground screen connections exposed to heat cycles
dc.typeMaster thesis


Tilhørende fil(er)

Thumbnail
Thumbnail

Denne innførselen finnes i følgende samling(er)

Vis enkel innførsel