Andrianto. Abstract. 2019. This paper presents the maintenance scheduling of transformer oil in
Banaran Substation, Indonesia. Based on data from the annual maintenance of
transformer oil, the value of reliability and availability has decreased. The
function of the transformer is important to distribute electricity. If there was a
fault, it can decrease the reliability of the transformer. One such problem is
damage to the oil transformers. Therefore, it is necessary to schedule the periodic
maintenance of transformer oil to improve the power transformer reliability.
So in this research using Markov method to analyze the reliability and
availability of transformer oil. It happened because of Markov method can
increase estimates effectively and able to produce information that can be used to
assist decision making. This research adds the used parameters, namely the results
of the DGA test with TDCG and the results breakdown voltage test. These
parameters will be processed by using Markov method to find the value of
reliability and availability with calculated using the failure rate (λ) and the repair
rate (μ). Where the value is obtained from the calculation of MTTF and MTTR.
The calculation results are simulated using Matlab R2014a, and the results
show us that the reliability and availability of transformer oil decrease every
month. The biggest decrease occurred on day 180 in a period of 365 days, with
the value of TDCG is 9.844% and 3.395% while the value of breakdown voltage
is 32.19% and 24.83%. The temperature conditions of the transformer oil every time the test is in
an overheating condition or in a bad condition. The total value of TDCG
reliability and breakdown voltage is 0.378 within 365 days. So that transformer oil
needs to be filtered. Therefore, maintenance is carried out at least twice a year to
improve the quality of transformer oil which functions as an isolation transformer
and prevents transformer failure.