Analisis Penyebab Gangguan Pada Transformator Tenaga II -30 MVA 150 kV/20 kV Di Gardu Induk Mrica

Sari

Operation of the transformer along with age, and the level of loading is given, slowly the transformer oil and paper insulation will deterioration. Some of the cause is due to over voltage, high operating temperatures, hot spots, corona, partial disharge, contamination, mechanical damage and moisture. The chronological disorder transformer 2-30 MVA in Mrica substation was on November 1, 2011 at 02:53 with an indication differential relay phasa S and T, OCR relay phase S and T, and the internal relay Bucholz, Sudden preasure, and Jansen. To determine the type of disturbances on the transformer, then do testing on transformer, transformer oil testing and shutdown measurement testing. DGA tests are known by the number of hydrogen content of more than 50% of TDCG, this indicates arching in oil and tangen delta values in excess of 1%, it can be concluded that the failure isolation transformer, causing a short circuit in the transformer. to find out how to decrease the isolation process, then do an analysis of the test data DGA, characteristics, and shutdown measurement testing before disturbance, to determine the rate of decline in the isolation transformer. From the results of the DGA test there was the increase in the value of CO2 exceeds 50% of the gradual TDCG in each year, as well as valuable CO2/CO ratio< 3 and > than 10, it was occurrence the deterioration in the paper cellulosa. On the characteristics testing found decreased in the value of interfacial tension less than 22 dyne / cm, and and color levels on the value of 4.8 with a yellow brown color, this conclude occurrence  oxidation on oil and deterioration in the paper cellulosa.                Keywords : Transformer, disturbance, Arching, Insulation, DGA, Characteristik.