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ProTrafo - Next Generation Protection of Transformers

The transformer is one of the key components in any electric power system. Its purpose is to convert between different voltage levels, thereby enabling transmission of power over long distances, and the distribution of power to the end customer. The failure of a transformer leads to substantial costs for the owner and often loss of power as well.

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Distribution transformer

The transformer is connected to an electric power system that operates with 50 Hz sinusoidal voltages. In addition, the transformer experiences additional stresses from transient (short duration) overvoltages that are caused by lightning discharges, normal switching operations in the system (system reconfiguration) and fault incidents. Such transient overvoltages can have a very high peak voltage and include high frequency components as well (often up to 1 MHz), thereby posing a risk to failure of the transformer insulation system. It is therefore necessary to fit the transformers with some protection system that reduces the overvoltages to a sufficiently low level.

The objective of the project is to provide improved capabilities for determining the overvoltages by simulation in software programs. That way, the potential overvoltages can be predicted and the most suitable protection scheme be selected. The project activities include advanced modeling of key components (transformer, grounding system), inclusion of such models in simulation programs, simulation studies, and best practices for overvoltage protection (grounding system, surge arresters, RC snubbers,...). The effect of climatic changes on lightning activity is also included.

The project results will be documented in REN white papers.


Projectadminstration: Rasjonell Elektrisk Nettvirksomhet AS (REN) norwegian only

  • SINTEF Energi
  • Norges Vassdrags- og energidirektorat (NVE)
  • Metorologisk institutt
  • Hafslund Nett
  • Eidsiva Nett
  • Agder Energi Nett
  • Skagerak nett
  • Møre Trafo
  • Mørenett
  • Stange Energi Nett
  • Sykkylven Energi
  • Gudbrandsdal Energi
  • Tysnes Kraftlag
  • Skjåk Energi
  • Vang Energiverk
  • Royal SMIT Transformers B.V.
  • RTE - National Center for Grid Expertise

Key Factors

Project duration

2017 - 2020

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