CONDITION MONITORING AND DETERMINATION OF MAINTENANCE PRIORITIES FOR 20KV DISTRIBUTION TRANSFORMERS USING ANALYTICAL HIERARCHY PROCESS METHOD

• Main Author: Suharly, Rizki
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/87109
• Institution: Institut Teknologi Bandung

The distribution system is one part of the electrical utility system. The most crucial asset in the distribution system is the distribution transformer. The high failure rate of transformers can lead to loss of revenue and a decline in service quality. There are many factors that cause failures in transformers. Therefore, developing a strategic plan to improve transformer reliability is a necessity. One of the strategic plans to support transformer reliability is through condition monitoring and determining maintenance priority indices based on the Health Index (HI). One of the aspects that most affects the accuracy level of HI is the weighting factor. Based on previous studies, there are several methods for determining the weighting factors in HI. In this study, the method used is the Analytical Hierarchy Process (AHP) involving expert assessments to adjust the weighting values. The involvement of experts with knowledge and experience in the relevant field can help improve the accuracy level and the approach to the actual conditions in the field. Weighting factors are applied to several transformer condition parameters (transformer oil leakage, physical condition, grounding, load imbalance, load profile, and temperature condition). The determination of weighting using AHP resulted in temperature as the parameter with the highest weighting (0.23), followed by load profile (0.20), load imbalance (0.18), oil leakage (0.17), grounding (0.12), and physical condition (0.06). After obtaining the weighting factor values, 539 samples of 20 kV distribution transformers in operating condition were monitored and assessed using the Health Index. The samples used in this study have varying transformer capacities and ages. The results of the HI calculation on 539 samples showed that there were 147 units in good condition, 328 units in fair condition, 56 units in poor condition, and 8 units in bad condition. The priority index obtained serves as the basis for determining the priority of maintenance activities. To determine the accuracy level of the assessment, the HI on the transformer can be compared with the number of anomalies in the tested parameters and compared with the historical disturbances of the tested transformers.