Risk-Based Prioritization Method for Rescheduling Delayed Preventive Maintenance of Electric Power Transmission Assets

PT PLN (Persero) West Java Transmission Main Unit (UITJBB) is one of the units of PT PLN (Persero) that has a strategic role in the electricity business in DKI Jakarta and Banten. UITJBB serves VVIP, Zero Down Time Area, High Voltage Consumers, and Regular Consumers. Being part of a strategic electricity system, UITJBB’s core business is to distribute electricity from power plants to consumers in the western part of Java and ensure the availability and reliability of transmission equipment. To maintain the reliability and availability of the equipment, there are two types of maintenance applied in UITJBB, namely time-based maintenance and condition-based maintenance. Time-based maintenance is conducted at certain intervals, such as conducting maintenance on transformers every 2 years. All procedures and standards for performing preventive maintenance have been explained in the PLN Director’s Decision. However, due to the complexity of the transmission network and the criticality of the customers served, not all of the item able to be tested. Furthermore, due to the workability i.e., planned outage for maintenance, the time-based maintenance could not be executed. This problem will impact the difficulties to assess the asset condition (health index). There is risk that we cannot measure the ageing of the asset. Delayed preventive maintenance has become a recurring problem every year. The risk of damage to substation and transmission equipment due to the lack of preventive maintenance. In 2019, it was recorded that 33 percent of preventive maintenance was delayed out of the total planned maintenance, with 47 percent of the cases caused by system conditions and 22 percent caused by standby time. Rescheduling of delayed preventive maintenance is not optimal because there is no comprehensive and quantitative method available. This paper discusses the approach used to assess the risk of assets due to deferred maintenance, the increased risk value if maintenance is delayed for too long, and considerations for rescheduling. The expected result from this method is to reschedule the postponed preventive maintenance based on risk assessment, so that it becomes more optimal and serves as a basis for decision-making for the management to align with the company’s values.