What is Solid State Transformer (SST)

A solid state transformer (SST) alternately known as “smart transformer,” is a modern electrical energy device that offers bi-directional power flow. It is an amalgamation of high-powered semiconductor components, control circuitry and conventional high frequency transformers, offering reactive power compensation, harmonics reduction, and many others.  Solid state transformers cater to a wide variety of applications, ranging from alternative power generation to traction locomotives, power grid and electric industries, and others. Solid state transformers are used in a wide range of applications, which would facilitate the smooth transition from AC to DC and DC to AC, besides voltage conversion. However, alternative power generation is the most dominant application of solid state transformers.

Unlike a traditional transformer, solid state transformer provides an option for DC output of required magnitude as well. In a typical solid state transformer, the incoming voltage is converted into high-frequency AC with the uses of power electronic-based converter and then feed to the primary side of the high-frequency transformer. The opposite procedure is performed on the secondary side of high-frequency transformers to get the desired AC or DC or both kinds of output for the supply to load. The power transfer at a high frequency leads to reduction in weight as well as reduction in the size of a transformer.

Many of the advantages with solid state transformers come through reductions in size. Today, planting a transformer is not an easy task. Considerations like transportation, site preparation, installation and transmission costs all add to the budget. By contrast, smaller, cheaper solid state transformers could be relatively easily planted in small solar fields or storage pods. The faster switching speed of solid state devices would in turn make it easier for a utility to handle a multiplicity of power sources feeding into the grid because you'd have more transformers controlling and fine-tuning power quality.