The CT comprehensive tester is developed on the basis of the original successful development of the instrument transformer calibrator and the detailed analysis of the mathematical model of the instrument transformer. The instrument can measure the volt ampere characteristic and curve, 5% and 10% error curve, direct resistance and ratio polarity of CT according to the national standard: it can directly measure the ratio of voltage transformer; it can measure the bushing CT installed in the transformer. It can measure the ratio difference and polarity of voltage transformer qualitatively; it can measure the actual secondary load of current and voltage transformer on site. The instrument adopts DC and AC power supply with high accuracy and automatic linear regulation; digital processing module with high speed and reliability; high power output power supply is required to meet the test requirements, and it is also convenient for the test personnel to use and carry; the pre measuring circuit with high measurement accuracy and stability ensures the accuracy and high stability of the instrument measurement. It can be used in high temperature, high humidity, sea, desert, extremely cold, high altitude and other harsh environments. In addition, the instrument adopts the 320x240 large liquid crystal (the liquid crystal screen which can work at low temperature can be selected in the north area) full Chinese interface platform technology newly developed by the company. It has human-computer interface, prompt wiring and operation, and any measurement parameter storage and measurement result printing function. (built in high-power transformer integrated tester. Can be tested continuously)