Implementation and Evaluation a SIMULINK Model of a Distance Relay


Evaluation This paper describes the opportunity of implementing a model of a Mho type distance relay with a three zones by using MATLAB/SIMULINK package. SimPowerSystem toolbox was used for detailed modeling of distance relay, transmission line and fault simulation. The proposed model was verified under different tests, such as fault detection which includes single line to ground (SLG) fault, double line fault (LL), LLG

double line to ground fault (LLG) and three phase fault, all types of faults were applied at different locations to test this model. Also the Mho R- jX plain was created inside this model to show the trajectory of measured apparent impedance by the relay. The results show that the relay operates correctly under different locations for each fault type. The difficulties in understanding distance relay can be cleared by using MATLAB/SIMULINK software.


  1. Power system protection
  2. Distance relay
  3. Line protection
  5. Apparent Impedance



Figure 1. Overall simulation model


A Mho type distance relay was successfully developed based on MATLAB/SIMULINK package, (each part of the relay is implemented as a separate function). Each function has been created using special blocks of SIMULINK. By testing the behavior of the developed relay model under different fault conditions, the relay model was able to recognize the appropriate fault type.


From perspective impedance calculations, the relay model has the ability of indicating the correct zone of operation in all cases. The relay identifiers the fault locations as expected, as the fault location is changed, the measured impedance change consequently. The impedance path which reflects the behavior of the model under different fault conditions was presented and discussed


[1] Anderson. P.M.”Power System Protection”, ISBN 0-07-134323-7 McGraw-Hill,1999.

[2] Muhd Hafizi Idris, Mohd Saufi Ahmad, Ahmad Zaidi Abdullah, Surya Hardi “Adaptive Mho Type Distance Relaying Scheme with Fault Resistance Compensation” 2013 IEEE 7th International Power Engineering and Optimization Conference (PEOCO2013), Langkawi, June 2013.

[3] M. H. Idris, S. Hardi and M. Z. Hassan, “Teaching Distance Relay Using Matlab/Simulink Graphical User Interface”, Malaysian Technical Universities Conference on Engineering and Technology,

November 2012.

[4] L. C. Wu, C. W. Liu and C. S. Chen, “Modeling and testing of a digital distance relay using Matlab/Simulink”, IEEE 2005.

[5] The Math Works, Inc., “SimPowerSystems user‟s guide”, Version 4.6, 2008.

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