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.
![HM launched its first SF6 Gas Insulated Vacuum OLTC in 2014 with the world highest voltage level]( "HM launched its first SF6 Gas Insulated Vacuum OLTC in 2014 with the world highest voltage level")
Diverter Switch
l 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 Selector
l Use the mature overall structure of CMD selector.
l All the contacts are designed as rolling structures.
Advantages of HM SF6 Gas Insulated Vacuum OLTC
l Non-flammability
l Easy inspection and less maintenance work
![HM launched its first SF6 Gas Insulated Vacuum OLTC in 2014 with the world highest voltage level]( "HM launched its first SF6 Gas Insulated Vacuum OLTC in 2014 with the world highest voltage level")
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 test
2. OLTC Mechanical test
3. Contact temperature-rise test
4. Switching test
5. Short-circuit current test
6. Transition impedance test
7. Insulation test
On 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.