Electrical Characterisation of Silicone Oil (ECOSO)

Completed

Other Power and Storage Technologies(Electricity transmission and distribution)

Applied Research and Development

ENGINEERING AND TECHNOLOGY (Electrical and Electronic Engineering)
ENGINEERING AND TECHNOLOGY (Mechanical, Aeronautical and Manufacturing Engineering)

Not Cross-cutting

Project Contact
National Grid Electricity Transmission

Network Innovation Allowance

Ofgem

01 June 2018

31 July 2021

ENA months

£632,000

Power

London

Network Innovation Allowance

Project Contact, National Grid Electricity Transmission

Project Contact, National Grid plc

The proposed method to solve the problem is experiment based. Extensive high voltage tests will be conducted to simulate the discharge causing degradation in silicone oils and along silicone oil/solid interface by considering a range of factors including contamination, degradation and oil type. Multiple diagnostic means including PD detection, high speed imaging and chemical analysis will be used to characterize the degradation process.Based on the results, a better understanding on the effect of contamination and degradation on discharge/breakdown degradation mechanism can be gained. Information of degradation modes and useful diagnostic parameters can be extracted to inform the insulation condition assessment of the CSEs. This project will investigate: 1, Partial discharge characteristics in silicone oils under a wide range of insulation conditions.2, Creepage discharge characteristics along silicone oil/solid insulation interface under a wide range of insulation conditions.3, Effect of thermal ageing/degradation on the discharge performance of silicone oil/solid insulation system. The objectives of the project include:1, To understand the effect of contamination and degradation on discharge/breakdown degradation process in silicone oil/solid insulation system of the CSEs.2, To propose the useful diagnostic parameters which can contribute to the insulation condition assessment of the CSEs.

National Grid ET (NGET) currently has a population of several thousand Sealing Ends (SEs) of all types (including fluid filled and XLPE) across Great Britain. With the expected increase in undergrounding technologies and the difficulties with new OHL routes, NGs SE population is expected to increase. Experience has shown that since rapid uptake of XLPE cables in the early 2000s, that the Cable Sealing Ends (CSEs) used to terminate the cables have suffered several bulk replacements due to performance issues; for different reasons. Which has required NG to manage the increased risk presented by these assets during their early replacement, and has ultimately led to a rapid replacement timeline. With the advent of Condition Monitoring Surveys (CMS), there is opportunity to identify the poor condition assets and manage their risk effectively, without the need for immediate replacement. However, there is a lack of understanding on the degradation mechanisms for silicone oil filled CSEs, in particular the interaction between oil contamination/degradation and discharge/breakdown process for silicone oils used in these CSEs. This poses challenges to conducting effective assessment of the condition of the CSEs in order to inform the management of CSEs, their replacement strategy and manage their end-of-life.

09/11/22