Modelling of overcurrent relay with inverse characteristics for radial feeder protection using graphical user interface

The paper describes the modeling and implementation of overcurrent relay with different overcurrent characteristics using MATLAB/Simulink. A Simulink block with generic design of overcurrent relay is designed incorporating IEC and IEEE standards and is ready to be used for any power system protection scheme. Consequently, the performance of the Simulink block is validated and IDMT Standard inverse characteristic curve is obtained for different values of Time Multiplier Settings and Plug Setting Multipliers. Furthermore the performance of software model is tested on radial feeder protection, simulated in Simulink environment. In addition to that a user-friendly Graphical User Interface is designed in way that user can easily operate radial feeder protection scheme by setting relays at different parameters and check the performance and reliability of the network for different fault locations. The overall effort focusses in teaching and improving learning experiences of student undertaking Power System Protection course. Moreover this software block of digital relay can be tested on any real time protection scheme involving IDMT overcurrent relay, within Simulink Environment.