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Övertoner i kemisk industri: Harmonics in chemical industry
Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
2016 (Swedish)Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
Abstract [en]

Disturbance in the power grids is a problem that is spread worldwide and have negative effect

on the power quality. It also gives unwanted costs for consumers as well as producers of

electrical power. The main reason to problems with the power quality is the increasing use of

non-linear loads connected to the power grid. The term “Power quality” is used to define the

quality present in the power system. The typical disturbances in the power system are

harmonics, change in voltage and transients. By measuring and analysing a result can be

given to see what arrangements might be necessary to increase the power quality.

Akzo Nobel Pulp & Performance Chemicals AB is an industry who mainly

produces bleaching chemicals. In the process a large amount of electrical energy is needed

and problems in the power quality have occurred multiple times. The main issue is the

generation of harmonics which is spread to the connected power grid. They want to minimize

the spread of harmonics to help increasing the power quality in the internal system and the

external grid. The plant is connected to 70 kV incoming voltage which supplies the loads via

the switchgear. The loads mainly consist of rectifiers and variable frequency drives.

The reason this study has been conducted is to gather information and measurements as an

initial start for a larger investigation for larger study for an installation of a harmonic filter.

This report will show measurements of the harmonic’s being presence, filtering methods

available and some proposals for the larger study and how to minimize the harmonic

generation.

To get an understanding on harmonics studies has been done on theories on the topic such as

Power quality, Fourier analysis and filtering methods being available. Some studies on the

type of non-linear loads connected in the plant such as rectifiers and variable frequency drives

has been done as well. Measurements in the main switchgear of the three supplying phases in

the point of common coupling have been done.

The results show that the level of harmonics exceeds the given limit at many times. And the

given limit is only fulfilled with reduced use of power by the plant. The main harmonic that

contributes in exceeding the given limit is the 7:th harmonic, which makes sense with the

theory in harmonic generation given by rectifiers and variable frequency drives. The 5:th

harmonic should be more present based on the same theories, but they are not. This is

considered to be because of a phase shift between the loads connected. The even harmonics is

seen in the system as well which indicates a non-symmetrical case for the system. The nonsymmetrical

case are within acceptable limits. Filtering are necessary to keep the level of

harmonics under the limit. A planning in locating the loads should also be considered with the

harmonics in mind for future changes in the system.

Place, publisher, year, edition, pages
2016. , 31 p.
Keyword [en]
Harmonics, Power Quality
Keyword [sv]
Övertoner, Elkvalité
National Category
Energy Engineering
Identifiers
URN: urn:nbn:se:umu:diva-127518OAI: oai:DiVA.org:umu-127518DiVA: diva2:1046695
External cooperation
AkzoNobel
Subject / course
Energiteknik
Educational program
Bachelor of Science Programme in Energy Engineering
Presentation
2016-10-31, TA206, X, Håken Gullessons väg 20, Teknikhuset, Umeå, 13:00 (Swedish)
Supervisors
Examiners
Available from: 2016-11-15 Created: 2016-11-14 Last updated: 2016-11-15Bibliographically approved

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  • nn-NO
  • nn-NB
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