ZYD series special designed for purifying the insulating oil in all kinds of large power equipments, especially are above 110kv, it equips a vacuum pump and a booster pump, producing extremly high vacuum, suitable for transformer oil filtration & transformer vacuum pumping for various on-site projects of power transmission and generation stations. It removes trace water, gas and impurities from insulating dielectric oil/transformer oil, improving the insulating oil properties.