Smart Transformer

The transformer has been used throughout the twentieth century. Until now, it has consisted of a configuration of iron or steel cores and copper/aluminum coils, with mineral oil serving as both coolants a dielectric medium. A new kind of power electronics transformer is developed one that can be made self-regulating, coil free, and able to correct power quality problems. Solid State Transformer (SST) has been regarded as one of the most emerging technologies in the electrical power system. It is a collection of high-powered semiconductor components, conventional high-frequency transformers and control circuitry which is used to provide a high level of flexible control to power distribution networks. It has the advantages of low volume, low weight, fault isolation and potential additional functions, such as voltage regulation, reactive power compensation, and etc. The purpose of this article is to give the idea about this developing power electronic transformer also known as Solid state transformer. The brief review of various developments in SST technology is given here.


Smart transformer is a solid-state device that serves as a power load with the ability to distribute and provide optimal power to loads. This “intelligent device” is a composed of some sophisticated electrical hardware like high-powered semiconductor components, conventional high-frequency transformers and control circuitry whose purpose is to arrange a high level of supple control to power distribution networks. If some communication capability is added to this arrangement then the resulting setup would be known as a smart solid state transformer.

Function of Solid State Transformer

In this transformer use transistors and diodes and other semiconductor-based devices that, unlike the transistors used in computer chips, are engineered to handle high power levels and very fast switching. In response to signals from a utility or a home, they can change the voltage and other characteristics of the power they produce. They can put out either AC or DC power, or take in AC and DC power from wind turbines and solar panels and change the frequency and voltage to what's needed for the grid. They have processors and communications hardware built in, allowing them to communicate with utility operators, other smart transformers, and consumers.

Application of Solid State Transformer

  • Application as interface for distributed generation and smart grids - Distributed energy sources, such as photo-voltaic arrays and wind turbines, provide a variety of electric sources.
  • Offshore energy generation systems (wind, tidal or any other source) and smart (power) grids.
  • Locomotives and other traction systems – The transformer used in current locomotive vehicles is 16.7Hz and is ±15% of the total weight of the locomotive.
  • They are capable of converting the output from DC to AC and they can also take in DC and AC power from the source and revise the frequency and voltage according the requirements of the grid.
  • Electric Vehicle Charging Stations.

Advantage of Solid State Transformer

  • The Solid State Transformers can achieve unity power factor.
  • These transformers have the ability to deliver diverse power like 400 Hz services.
  • The SST concept is ideally suited efficiency in power transmission. 
  • Improve voltage regulation.

Disadvantage of Solid State Transformer

There is a major hurdle or disadvantage that has hindered its large scale production. It is based on semiconductor devices and currently there are no semiconducting material arrangements that can handle as much as 10kV grid allocation voltage.


With the increase in use of renewable energy and distributed energy sources, use of traditional transformers has increased the complexity of the electrical power grids. In order to overcome this complexity, there is need to adopt newer technologies to ensure better control and more reliable operation of the grid. In this article, technological review of concepts and developments in field of Solid State Transformer has been shown.


  1. Online Link: 
  2. Online Link: https://w/ 
  3. Online D.K. Rathod Solid State Transformer (SST) “Review of Recent Developments” Advance in Electronic and Electric Engineering. Volume 4, Number 1 (2014), pp. 45-50
  4. Online Link: smart-solid-state-transformers.html


Ravish Kumar, B.Tech Scholar, Electrical and Electronics Engineering Department, PHONICS Group of Institutions, Roorkee, Uttarakhand, India, 2019.

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