Novel O-Ring Designs (NORD)

Completed

Other Power and Storage Technologies(Electricity transmission and distribution)

Applied Research and Development

ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering)

Not Cross-cutting

Project Contact
National Grid Electricity Transmission

Network Innovation Allowance

Ofgem

01 March 2019

31 July 2021

ENA months

£392,000

Power

London

Network Innovation Allowance

Project Contact, National Grid Electricity Transmission

Project Contact, National Grid plc

This project will investigate the performance of different O-ring seal topologies, for a range of bushings and CSEs. The structure and performance of these O-ring designs will be investigated to understand how they operate and how their performance might degrade overtime. Ageing mechanisms such as mechanical & thermal degradation, elastic creepage, and chemical interactions will all be investigated. Once the ageing mechanisms have been reviewed and critical ones identified, a suitable synthetic test environment will be developed to test the performance. This synthetic test environment will be used to classify the performance of different O-ring designs.Once the existing O-rings designs have been understood and benchmarked, novel O-ring materials and designs will be investigated for these applications. This project will investigate: 1 - Review of current designs, materials and existing relevant technology2 - Characterise existing O-rings topologies3 - Develop a testing methodology and test seals under representative conditions.4 - Development of finite element model and its use to investigate seal performance.5 - Investigate the potential for the use of new materials and assessment of improved designs The objectives of the project include:1 - To understand the performance and degradation of O-ring seals used in transformer bushings and CSEs.2 - Develop a synthetic test environment to test O-rings, which replicates the in-service environment.3 - Assess the application of novel materials for use in O-ring seals for bushings and CSEs.

Moisture ingress is a life limiting factor for many assets, due to the degrading nature that water has on the performance of electrical insulators. For oil filled assets, moisture can result in degradation processes being accelerated. This ultimately results in assets being replaced sooner in their lives, or requires that maintenance activities must take place sooner. Replacing an asset sooner in its life, results in the consumer paying more for non-load related works, while an increase in the maintenance activities increases the Whole Live Cost(WLC) of assets.National Grid ET (NGET) has identified several families of bushings and Cable Sealing End (CSE) which are thought to have problems with moisture ingress. Many types of bushing and CSE use O-rings to prevent moisture ingress; however different designs appear to be more successful at keeping moisture out than others.NGET also has evidence that moisture will naturally creep into these assets over time; based on existing data that shows a linear increase in moisture with the age of asset. As there are critical thresholds for bushings and CSEs in terms of the maximum moisture levels, understanding the performance of these seals and when these thresholds are likely to be exceeded is essential to effective condition based management of these assets.

09/11/22