Medium Voltage Gas Insulated Ring Main Unit (RMU) Condition Assessment by Utilizing Health Index Monitoring Method in Malaysia Power Utility

This paper proposes a comprehensive method to evaluate the condition of Gas Insulated Ring Main Unit (RMU) by using the conventional weight and scoring method cojoin with risk factor to improve the accuracy of the Health Index (HI) evaluation. Currently in Malaysia Power Utility implements Condition Based Monitoring (CBM) as a method to assess the condition of RMU. However, the CBM data captured never been integrated into HI method. Thus, overall health condition difficult to determine without overall overview of RMU condition. The HI evaluation proposed is utilizing CBM data being transformed to a numerical value in term of percentage according to respective compartment up to overall HI. The accuracy of the HI has been improved by applying risk factor which considers invisible aspect that can contribute to the changes of the index. In this paper, a condition evaluation method has been developed. Subsequently, the method has been developed to evaluate 200 numbers of 11kV distribution RMU. Recommendation of maintenance strategy has been developed as well based on HI result to optimize resources and cost management. Thus, this study contributes an overview and insight condition of RMU in indexing form and provide input for maintenance strategy plan or repair.