A high voltage bushing is one of the most critical components in a power transformer. Failure statistics for power transformers show that bushings are one of the three main contributors to a transformer failure. Bushing failures has huge catastrophic impact to reliability and safety of the system and operators managing the asset. Therefore, three major ASEAN utilities embarked on a joint bushing reliability survey study and formulated mitigative measures to improve bushing performance. The survey summarises the failure and root cause of each participating utilities from year 2001 till 2015 with different practices among the members. Improvements in terms of selection, specifications, design, condition assessment, storage and handling of bushings are deemed necessary and has a huge impact on the safety and performance of a transformer and grid network as whole. Existing maintenance practices, standards, bushing technologies such as oil impregnated paper bushings (OIP) and resin impregnated paper bushings (RIP) are well established in the industry, although they have some disadvantages. The disadvantages of practices are mainly differences in existing maintenance strategies and standard's acceptance criteria to address bushing degradation and also non-standardised dimensional requirements for ease of maintenance and strategic spare requirements. The disadvantages of an OIP bushing are mainly related to fire risk and environmental problems, meanwhile for RIP bushings moisture uptake during storage is a major issue. Therefore, these disadvantages are addressed individually to formulate an action plan to improve its performance. Looking forward, some member also embarked on the new technology solutions alike resin impregnated synthetics bushings (RIS) and RIP moisture barriers technology which currently under evaluation.
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