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Probabilistic Approach to InsulationCoordination
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
2016 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

The present work was performed at HVDC

ABB as an initial study on how to adopt

probabilistic concepts into the VCSHVDC

insulation coordination.

Due to large voltage levels in HVDC

applications the corresponding

insulation need to be properly

addressed to ensure a safe, economical

and reliable operation. Traditionally,

only the maximum overvoltage is

considered, where no adoption to the

shape of the overvoltage distribution

is regarded. Use of probabilistic

concepts in the insulation coordination

procedure can ideally reduce insulation

margins with a maintained low risk of

flashover. Analysis and understanding

of probabilistic concepts of AC systems

is needed in order to implement the

concepts into VSC-HVDC.

With use of advanced VSC-HVDC models,

faults are simulated with varied fault

insertion time in PSCAD. The resulting

overvoltages from the simulation is

gathered using different statistical

methods in order to obtain the

approximated overvoltage distribution.

It was found from the simulation

results that use of a Gaussian

distribution is inappropriate due to

shape variety in the overvoltage

distributions. Instead, Kernel Density

Estimate can serve as a flexible tool

to approximate overvoltage

distributions with a variety in number

of modes and shape. The retrieved

approximated overvoltage distributions

are compared with the insulation

strength in order to calculate the risk

of flashover. The comparison shows that

the insulation can be tuned in order to

match set requirements. The thesis work

should be seen as pilot study, where

key problems have been pointed out and

recommended further studies are


Place, publisher, year, edition, pages
UPTEC F, ISSN 1401-5757 ; 16020
Keyword [en]
VSC-HVDC, KDE, Insulation coordination
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
URN: urn:nbn:se:uu:diva-296483OAI: diva2:938552
External cooperation
Educational program
Master Programme in Engineering Physics
Available from: 2016-06-17 Created: 2016-06-17 Last updated: 2016-06-17Bibliographically approved

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