TET4130 - Overvoltages and Overvoltage Protection


Examination arrangement

Examination arrangement: Written examination
Grade: Letters

Evaluation form Weighting Duration Examination aids Grade deviation
Written examination 100/100 4 hours D

Course content

Analysis of disturbances as current and voltage transients in electrical networks. Description and calculation of travelling waves on lossless electrical conductors along with measuring techniques related to fast voltage variations. Ligthning overvoltages in high and low voltage systems, lightning protection and lightning induced overvoltages. Switching overvoltages and temporary overvoltages. Establishing ideal computational models valid for the voltage and frequency ranges represented by the overvoltages. Impact of grounding conditions and grounding resistance. Description of different types of overvoltage protection in both high and low voltage systems with a focus on metal oxide arresters. Overview on dimensioning and location of protection in the system to avoid damage to equipment. Introduction to computer calculation of transients.

Learning outcome

After completing this course the candidate shall:
- understand the source and characteristics of lightning, switching, and temporary overvoltages.
- understand travelling wave propagation on transmission lines.
- understand the critical switching transient situations.
- be able to set up differential equations for RLC circuits and solve it via stationary and transient solutions.
- understand the mode of operation and dimentioning criteria for surge arresters.
- understand the physical and electrical construction of high voltage systems.

After completing this course the candidate shall be able to:
- contribute to a reliable operation of high voltage systems.
- carry out simple, analytical calculations of overvoltages and currents in power systems.
- set up lattice diagrams and make calculation in systems with two reflection points.
- utilize EMTP programs in a critical and effective way for calculation of power system transients.
- dimentioning surge arresters in power systems.

The student will also have increased his/hers abilities to use instruments and equipment in the laboratory.

Learning methods and activities

Lectures. Compulsory exercises, computer exercise, laboratory experiments. If there is a re-sit examination, the examination form may change from written to oral.

Compulsory assignments

  • Laboratory work with report
  • Computer exercise with report
  • Exercises

Specific conditions

Exam registration requires that class registration is approved in the same semester. Compulsory activities from previous semester may be approved by the department.

Course materials

Printed compendium.

Credit reductions

Course code Reduction From To
SIE1030 7.5



Examination arrangement: Written examination

Term Evaluation form Weighting Examination aids Date Time Room *
Spring Written examination 100/100 D
* The location (room) for a written examination is published 3 days before examination date.
If more than one room is listed, you will find your room at Studentweb.