HM launched its first SF6 Gas Insulated Vacuum OLTC in 2014 with the world highest voltage level Keyword Concerning the continuous increasing power consumption in urban areas, a great number of substations have been constructed underground, beneath commercial buildings, parks and public spaces. In this case, gas insulated transformers offer the best solution due to their outstanding non-flammability and insulating efficiency. As the most crucial part of transformers, gas Insulated vacuum OLTCs were born accordingly. Boasting a professional and experienced design team, HM launched its first SF6 Gas Insulated Vacuum OLTC (Type: SHGVIII) successfully in 2014 and became a leader ofGas Insulated Vacuum OLTCs with the highest voltage level. Diverter Switchl Use Vacuum interrupter (EATON, USA) to extinguish arc.l The energy accumulation mechanism adopts the “over-dead–point” release principle, and all moving parts are rolling friction.l Take the heat dissipation problem of transition resistance into consideration and reduce the transition resistance flow density.Tap Selectorl Use the mature overall structure of CMD selector.l All the contacts are designed as rolling structures. Advantages of HM SF6 Gas Insulated Vacuum OLTCl Non-flammabilityl Easy inspection and less maintenance work Transformer SQFPZ11-63000/220±8*1.25%& SHGVIII-400Y/126C-10193G The SF6 Gas Insulated Vacuum OLTC passes all type tests as below in accordance with the requirements of IEC-60214-1 tap-changer Part 1: performance requirements and test methods. 1. OLTC functional test2. OLTC Mechanical test3. Contact temperature-rise test4. Switching test5. Short-circuit current test6. Transition impedance test7. Insulation testOn 21 July 2016, Power Grid Planning Research Center of Shenzhen Power Supply Bureau Co., Ltd issued a Statement to HM and certified the SF6 Gas Insulated Vacuum OLTC produced by HM operates very well at the 220V Yulv Substation in Qianhai, Shenzhen without any failure since commissioning.