Magnetic Models for Transformers

Completed

Other Power and Storage Technologies(Electricity transmission and distribution)

Applied Research and Development

PHYSICAL SCIENCES AND MATHEMATICS (Physics)
ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering)

Not Cross-cutting

Project Contact
National Grid Electricity Transmission

Network Innovation Allowance

Ofgem

01 September 2009

01 July 2016

82 months

£421,000

Power

London

Network Innovation Allowance

Project Contact, National Grid Electricity Transmission

The results from this project will be directly used within Electricity Transmission’s Asset Policy and Asset Engineering in analysing future and existing designs of transformer for operational aspects of ferroresonance, geomagnetically induced currents (GIC) and over-fluxing. The knowledge may also be useful in post event analysis. The project will have deemed to have been a success if the industry’s knowledge in this area has been progressed. National Grid will be able to measure this by an improved analysis of the operational aspects for the magnetic circuit of a transformer/QB under high induction conditions.

Currently there is no model for the magnetic circuit of a transformer/Quadrature Booster (QB) under high induction conditions, limiting the conclusions about the relationship between ferroresonance and transformer damage. This inability appears to be general throughout the transformer industry and represents a significant gap in knowledge. This gap is normally not important to transformer manufacturers because during tests the core of a transformer is operated well within flux limits, however during operation these limits can be exceeded and increasing the capability of transformers to avoid this would have a direct impact on initial cost. Conservative assumptions about core saturation have therefore had to be adopted, particularly in QB design because of a lack of knowledge. This project proposes the following methods; Develop finite element mathematical core model of simple core and core joint Validate the model against physical model core with and without joint. Develop bulk property constants for laminated core steel and joint areas Develop finite element model of complete large transformer core Use model in QB/transformer/reactor design to develop knowledge of operating envelope with respect to the magnetic circuitNote : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above

31/08/18