Planning of transformer placement using reliability in PLN Transmisi Jawa Bagian Barat

Nowadays, the population of installed transformer in PT PLN (Persero) Transmisi Jawa Bagian Barat is 305 units which consists of many variations of manufacturers and types. It consists of 21 manufacturers and 38 types along with different operational age from the young age transformers (under 20 years) until the old age transformers (more than 20 years). It means, TJBB needs different strategy for each transformer. For the old transformers, the strategies are whether relocating the transformer to another location and replacing it with new transformer or improving maintenance activities of the transformer to increase their reliability. While with the young transformer, TJBB has to plan the quantities of the spare will be needed. However, due to many variations of transformer manufacturers and types, it will be difficult when determining the number of spare and the type of maintenance. Meanwhile, the addition of the new transformer from the addition project or replacement project will be taking a role on the addition of the variations of manufacturers and types. Therefore, the information of the transformer performance is required. That information can be used to help the utilities to know the service performance of those various manufacturers, provide important inputs for utilities when specifying and buying transformer and also organize maintenance for transformer. In this paper, one of the information that stated above can be obtained by analyzing the failure that occurred on the transformer for the past few years. From the failure data, we will calculated the value of transformer reliability per manufacturer. The transformer reliability describes the probability of the existing population to survive beyond a certain age. This paper will discuss about the statistics of transformer failure that classified based on the voltage level, the cause of transformer failure and more focused on the current reliability level of transformer population which modeled by using weibull analysis into transformer reliability curve. In the reliability calculation, the failure data from each manufacturer will be grouped into a big group of manufacturer based on the similarity of the history of ownership and the technology used to manufacture the transformer. This paper have a purpose to determine transformer placement in PT PLN (Persero) Transmisi Jawa Bagian Barat by comparing the reliability with the type of location and customer that will be supplied.