There is a large number of electrical equipment in the power system, railway system and large petrochemical plant mines and enterprises, their internal insulation is mostly oil-filled insulation. The dielectric strength of insulating oil is a mandatory routine test. In order to meet the needs of the market, our company developed and produced a series of dielectric oil dielectric strength testers according to the national standard GB/T507-2002(IEC156), the standard DL429.9-91 and the latest power industry standard DL/T846.7-2004. This instrument takes the single-chip microcomputer as the core, realizes all the automation of the test, has high measurement precision, greatly improves the work efficiency, and greatly reduces the labor intensity of the staff. At the same time, the instrument has a compact appearance and is convenient to carry.