Gas chromatography is used by power sectors like Transformer factory, wire cannula factory and enterprises-power plant, power supply bureau that produce oil immersed electrical apparatus. It has adopted a system that opens the door from back and allows frequency conversion for automated cooling. The column compartment avoids pollution by heating up. The 3 gas paths can be equipped with columns that has three kinds of detectors like the ECD, FPD, NPD, external controlling equipment like gas injector and conversion furnace. It may also be packed by two column vaporization chamber and separated capillary system with split or non-split sampler chambers.