The Distribution Transformer is the last major equipment in the power supply chain and is supposed to work at all times to ensure continuous power supply to consumers. The Failure of a transformer disrupts power supply to all the consumers fed by it and results in inconvenience to consumers . Year after year thousands of transformers burnout, the repair cost which will sum up to large sums of money. Even after repairs when back in service they are re-exposed to work under same conditions risking repeated failures. Owners of distribution Transformers incurr huge cost of repair and loss of revenue for the period of outages in addition to loss of reputation. On the other hand consumers are greatly inconvenienced during the period of outages.

Causes for the Failure of Distribution Transformer :

The Excessive rise in the operating temperature is the main cause for transformer failure. Various Standards Such as IEC, BIS, and BS have Specified the operating Characteristics for transformers. These are known as “Thermal characteristics” and are typically specified for both hot and cold working conditions of the transformers. The Thermal Time constant which determines the time required to rise the temperature of the transformer depends on its size, weight and rating.

The Loading of the distribution transformer varies from light load to overload. The duration of over load may be continuous or cyclic. Again the loading pattern also varies during the time of the day, season of the year and nature of the load. Continuous changes in the internal temperature of the transformer will result in thermal stress on the internal insulation leading to progressive degradation of its property. Excessive operating temperature for extended duration will lead to burn out of insulation resulting in transformer failure.

Avoids Transformer failures and improve transformer management :

To Avoid distribution transformer burn-out, it is necessary to ensure its efficient and safe working at all times. The patented design of SMARTCON™–DT ensures that various causes that are determinental to the safe working of the transformers are adequately addressed to guarantee, years of trouble free performance of distribution transformers. SMARTCON™–DT also enables excellent management and control by measuring, Storing & Communicating various performance parameters of the distribution transformers.


  • Setting of SMARTCON is extremely simple
  • Multi-level password protection and tamper proof design
  • 2-way communication through communication port and GSM/GPRS network for distribution automation
  • Protection against Over Current phenomenon )
  • Protection against Over load phenomenon
  • Protection against undesirable voltage
  • Auto-reclose following Over Load
  • Auto-reclose after bus voltage stabilizes
  • Alarm indication to detect phase sequence reversal
  • Integrated control for Power Factor improvement (Optional)
  • Real time display of line voltages, currents and power factor
  • Exhaustive Fault and Event records facility
  • Exhaustive Load Flow Data to analyze the loading pattern



Causes for the Failure of Distribution Transformer :

SMARTCON™–DT is designed to facilitate operation, protection, control and management of distribution Transformer as per exact design and performance requirements. The thermal overload operating time is defined by the standard IEC 60255-8. Secondary current of all the phases are measured through line CTs. The thermal overload element will pick up when the load current is more than k*Ib ( where “ k “ is the thermal constant and Ib is the full load current of distribution Transformer). After a lapse of thermal overload operating time, the internal electromagnetic contactor will trip and disconnect full or partial load on the transformer and reduce further temperature rise and allow cooling of the transformer. An infinite number of automatic reclosing is provided following the thermal overload tripping. A single shot auto-reclosing is provided for tripping due to under/over voltage. The over current and earth fault threshold is provided in terms of k*Ib. If line current exceeds the threshold, then the relay extends trip signal after the operating time. The relay's operating time is determined by selecting any one of the two inverse time operating characterstics(IDMT). Independant curve selection & TMS is possible for phase overcurrent and earth fault protection. Optionally, a separate output contact is provided to achieve desired Power Factor. Visual Indication is provided for phase sequence monitoring. Load flow data, Event records and Fault records can also be downloaded on demand. Two way communication through GSM is achieved using any service provider's network.


  • Prevents Dist. Transformer Burn-Outs
  • Enhances Transformer life
  • Eliminates Service disruption
  • Increases revenue
  • Real time performance monitoring & Control
  • 2 Way communication using GSM & Storage of all measured value for down-loading on demand
  • Very short pay back period
  • Better utilisation of human resources

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