Introduction: Understanding transformer ferroresonance and other low frequency phenomena (GIC & switching) and its degrading mechanisms through power system & transformer modelling will enable better identification of the factors likely to lead to the failure of transformers. This will allow asset management to determine the likeliness of circuit configurations to cause transformer ferroresonance, the susceptibility of transformer family towards ferroresonance, to optimise circuit configuration and transformer fleet, and to ensure system reliability at a lower cost.

Objectives: It is aimed to establish the material impact when power transformers are exposed to ferroresonance and how an improved understanding can affect the detection and asset management of the entire transformer fleet. The work packages concentrate on:

• Characterisation of the degradation and failure mechanism in different designs of power transformers associated with ferroresonance. Establish what effect this has on the useful lifetime for a transformer

• Identify the design features of transformers which are susceptible to ferroresonance

• Establish a reliable ferroresonance detection technique, which can be incorporated into new transformer protection relays.