Advantage of in Service Condition Based Assessment for Transformers in enhancing the maintenance strategy

controlling the maintenance OPEX is one of the major challenges that any utility faces. The challenges lie in how to optimize the three main factors: risk, performance, and cost. Besides, no utility can depend on a unique type of maintenance, there is always a combination of a different kind of maintenance such as breakdown, preventive, risk-based, conditionbased,.. etc. So, what is the answer to this question: what type of maintenance needs to be followed to keep the transformer in service in with high performance? There is no specific answer to this question. Each type of maintenance can be applied based on the transformer`s operating environment. However, most of the utilities apply preventive and condition-based maintenance. To justify this answer, some data need to be analyzed to assess the maintenance performance and recommend what are enhancement need to be added. One of these approaches is to apply in service condition-based assessment to study the health of the assets based on the current maintenance practice. Furthermore, study both historical maintenance records and failure rates will help to understand the relationship between the effectiveness of maintenance and service efficiency. This relation can come in two shapes. One is to do the right things by developing a set of maintenance activities that need to be performed during the maintenance to ensure its effectiveness. Second, is to do things right by enhancing the maintenance crew capabilities and competencies to ensure high efficiency. After analyzing all these factors mentioned above, It has been noticed that in-service condition-based assessment of the transformer is a powerful tool that can be used to enhance and build an effective strategy. It will not only involve a set of activities during the maintenance, but it also covers the whole life cycle of the transformer. Besides, it highlights the gaps in the maintenance process and procedures, and provide indications where enhancement need to be applied based on international practice. These changes were observed on the cost and performance in the benchmarking study that was done through International Transmission Operation and Maintenance Study (ITOMS) which was a good indication of the effectiveness of strategy used for transformers. However, as part of the asset management approach, continuous improvement will continue to reach the vision that has been set in the maintenance optimization and to prepare for the future significant increase in transformer aging