This article is intended to act as a guide for basic calculations of secondary protection practices and setting procedure for DEMA MCR 310 Electronic Overcurrent Protection Relay. To form a basis for the calculations, a sample project with the single line diagram on the left is created. When evaluating the project, it must be noted that;

  •  The project and single line diagram is completely fiction,
  • The component ratings are given as sample values and may not necessarily represent any component ratings in the market,
  • The component selections are not based on engineering fundamentals thus must not be translated as selection suggestions or templates.

The following pdf contains calculations, estimations and graphics show the fundamentals of providing protection for a power transformer by using DEMA MCR 310 Electronic Overcurrent Protection Relay.