SF6 gas-insulated vacuum tap-changer

Introduction Rising urbanization leads to increase in population density, which poses big challenges for ensuring sufficient supply of electricity. Therefore, safety and fire resistance are...

byHuaming


Introduction

Rising urbanization leads to increase in population density, which poses big challenges for ensuring sufficient supply of electricity. Therefore, safety and fire resistance are taken as top priorities today in the construction of skyscrapers, shopping centers, metro systems, etc., considering that any electrical failure, especially in oil-insulated equipment, could cascade into catastrophic fire incidents.

So, what can we do to minimize the risk of transformer failure in densely populated areas?

Dry-type tap-changer solutions

In order to minimize the risk of transformer failure caused by malfunctioning tap-changer, Huaming has developed two types of solution. The first one is a dry-type tap-changer, which currently covers voltages up to 66 kV and the type covering voltages up to 132kV is already under research and development. The second solution, designed for higher voltages and capacities in heavy load centers, is the SF6 gas-insulated vacuum tap-changer SHGV, which has already been successfully in operation for some time.

SF6 is an odorless, non-flammable and non-toxic inert gas with stable chemical characteristics. Due to its high electro-negativity and fire immunity, it requires low maintenance. This gas has been widely used as a dielectric and cooling medium for high-voltage equipment since 1960s. It allows more compact design of transformers in terms of size and weight and extends transformer service time.

How we resolved design challenges

Huaming’s SHGV tap-changer is designed with all necessary features to address challenges posed by using SF6.

  • It is known that arcing in SF6 will generate hydrogen fluoride which is poisonous to human beings. To avoid arcing in the gas, vacuum interrupters are used to break the load. Today, vacuum switching in oil-immersed transformers is a mature technology. Based on tens of thousands of vacuum tap-changers delivered so far by Huaming, it was not a big problem for us to adapt a similar system to gas-insulated tap-changers.
To read the article, subscribe and choose the option which suits you best. We offer both free and paid options, and the registration takes only a minute.
Subscribe to Transformers Magazine