This research is presented by the designing and constructing test package that are divided into three types; the liquid insulator solid insulator and gas insulator. These materials are provided by in country in order to construct the test package for the results of expected to have at least error. This leads to reliability and validity in this study. The design of the liquid insulator of test package was conducted by the standard IEC 156 in which the material tested used oil transformer. Additionally its solid insulation was the range of catching objects and adjusting using the sheet of bakelite. Furthermore its gas insulation used acrylic was consisted of gas inside oxygen of pressure at 2 Bar. Three types of test could be supplied AC high voltage to test package causing of breakdown via insulators. After that taking note the value of breakdown was the liquid insulator of test material at 29.86kV its solid insulator at 36.32kV and its gas insulator (oxygen) at 48.40 kV

This article presents how the analysis an insulation of high voltage transformer bushing. The purpose is to analysis the moisture in the bushing to evaluate the approach for maintenance. The analysis rely on the principle of the Polarization and Depolarization Current (PDC) technique which is a technique for analyzing the insulation of high voltage equipment to test high voltage transformer bushing for a case study. This method is performed by energize 1000 Vdc into a bushing in period of time and then switch off the circuit for discharge current. Finally we calculate the moisture of main insulation of high volt bushing as well compare with standard moisture of criteria. The method is useful of preventive maintenance plane of high volt bushing and reduce the failure in the power system.