Analisis Umur Pakai Transformator Daya 2,5 MVA 6,6/0,42 kV 3 Phase Berdasarkan Beban Kerja dan Temperatur Operasi

Transformator daya merupakan salah satu peralatan utama dalam sistem tenaga listrik yang berperan dalam menjamin kontinuitas dan keandalan penyaluran energi listrik. Umur pakai transformator sangat dipengaruhi oleh kondisi pembebanan dan temperatur operasi, khususnya temperatur hot-spot yang dapat mempercepat proses penuaan isolasi. Penelitian ini bertujuan untuk menganalisis umur pakai transformator daya 2,5 MVA 6,6/0,42 kV 3 fasa berdasarkan beban kerja dan temperatur operasi yang terjadi selama periode pengamatan.
Metode penelitian yang digunakan mengacu pada standar IEEE C57.91-2011. Analisis dilakukan melalui perhitungan rasio pembebanan, kenaikan suhu top-oil, kenaikan suhu hot-spot, suhu hot-spot, Aging Acceleration Factor (FAA), Equivalent Aging Factor (FEQA), Loss of Life (LOL) transformator serta susut umur transformator. Data yang digunakan meliputi data beban transformator dan temperatur lingkungan yang kemudian diolah untuk menentukan tingkat penuaan isolasi serta estimasi sisa umur pakai transformator.
Hasil analisis menunjukkan bahwa peningkatan beban kerja menyebabkan kenaikan temperatur operasi transformator, terutama temperatur hot-spot, yang berpengaruh langsung terhadap percepatan penuaan isolasi. Hasil perhitungan Aging Acceleration Factor (FAA) dan Equivalent Aging Factor (FEQA) menunjukkan nilai antara 1,34 hingga 5,81. Nilai tertinggi terjadi pada kondisi pembebanan 0,8522 pu dengan temperatur titik panas 128,08°C, sedangkan nilai terendah terjadi pada pembebanan 0,7562 pu dengan temperatur titik panas 112,81°C. Hal ini menunjukkan bahwa temperatur operasi memiliki pengaruh yang signifikan terhadap percepatan penuaan isolasi transformator. Semakin tinggi temperatur titik panas, semakin besar nilai FAA dan FEQA yang dihasilkan. Sedangkan perhitungan Loss of Life (LOL), susut umur harian transformator berada pada rentang 0,018% hingga 0,077%, sedangkan susut umur bulanan berkisar antara 0,558% hingga 2,31%. Nilai LOL tertinggi diperoleh pada saat temperatur titik panas mencapai 128,08°C, sedangkan nilai LOL terendah terjadi pada temperatur titik panas 112,81°C. Hasil penelitian menunjukkan bahwa meskipun transformator masih beroperasi pada tingkat pembebanan di bawah kapasitas nominal, peningkatan temperatur operasi secara berkelanjutan dapat mempercepat degradasi isolasi dan mengurangi umur pakai transformator. Dari hasil perhitungan sesuai dengan Standard IEEE C57.91-2011 didapat bahwa susut umur trafo dalam satu tahun adalah 13,795% sekitar 24882 jam, sehingga susut umur trafo adalah 155118 jam (17,96 tahun).

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Power transformers are key components in electric power systems, playing a vital role in ensuring the continuity and reliability of electrical energy distribution. A transformer's service life is significantly influenced by loading conditions and operating temperatures—specifically the hot-spot temperature, which can accelerate the insulation aging process. This study aims to analyze the service life of a 2.5 MVA 6.6/0.42 kV 3-phase power transformer based on the workload and operating temperatures recorded during the observation period.
The research methodology employed follows the IEEE C57.91-2011 standard. The analysis involved calculating the loading ratio, top-oil temperature rise, hot-spot temperature rise, hot-spot temperature, Aging Acceleration Factor (FAA), Equivalent Aging Factor (FEQA), and transformer Loss of Life (LOL) and life depreciation. The data used to comprise transformer load and ambient temperature were processed to determine the rate of insulation aging and to estimate the transformer’s remaining service life.
The analysis results indicate that increased workload leads to a rise in transformer operating temperatures particularly the hot-spot temperature which directly accelerates insulation aging. Calculations of the Aging Acceleration Factor (FAA) and Equivalent Aging Factor (FEQA) yielded values ranging from 1.34 to 5.81. The highest values occurred at a loading of 0.8522 pu with a hot-spot temperature of 128.08°C, while the lowest values occurred at a loading of 0.7562 pu with a hot-spot temperature of 112.81°C. These findings demonstrate that operating temperature has a significant impact on the acceleration of transformer insulation aging; the higher the hot-spot temperature, the greater the resulting FAA and FEQA values. Regarding the Loss of Life (LOL) calculation, the transformer's daily loss of life ranged from 0.018% to 0.077%, while the monthly loss of life ranged from 0.558% to 2.31%. The highest LOL value was recorded when the hot-spot temperature reached 128.08°C, whereas the lowest LOL value occurred at a hot-spot temperature of 112.81°C. The results indicate that even when the transformer operates at a load level below its nominal capacity, sustained increases in operating temperature can accelerate insulation degradation and reduce the transformer's service life. Calculations based on the IEEE C57.91-2011 standard reveal an annual loss of life of 13.795% (approximately 24,882 hours), resulting in a total loss of life of 155,118 hours (17.96 years).