MATTER: International Journal of Science and Technology ISSN 2454-5880 146 Sujatha et al., 2017 Volume 3 Issue 1, pp. 146 - 158 Date of Publication: 11th March, 2017 DOI- https://dx.doi.org/10.20319/mijst.2017.s31.146158 This paper can be cited as: Sujatha, K. N., DurgaRao, R., & Shalini, V. B. (2017). Performance Analysis of Digital over Current Relays Under Different Fault Conditions in Radial and Parallel Feeders. MATTER: International Journal of Science and Technology, 3(1), 146 - 158. This work is licensed under the Creative Commons Attribution-Non Commercial 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc/4.0/ or send a letter to Creative Commons, PO Box 1866, Mountain View, CA 94042, USA. PERFORMANCE ANALYSIS OF DIGITAL OVER CURRENT RELAYS UNDER DIFFERENT FAULT CONDITIONS IN RADIAL AND PARALLEL FEEDERS K. Naga Sujatha JNTUH Kukatpally, Hyderabad, Telangana State, India knagasujatha@jntuh.ac.in R. DurgaRao JNTUH College of Engineering, Jagtial, Nachupally, Karimnagar, Telangana State, India ramisetti213@gmail.com V.B. Shalini JNTUH College of Engineering, Jagtial, Nachupally, Karimnagar, Telangana State, India shalini815@yahoo.com Abstract The conventional relays like electromechanical relays, static and microprocessor based digital relays are having their own disadvantages. Digital/ numeric relays are replacing to overcome these drawbacks. Digital protection devices are built with integrated functions and operated using digital binary values. Fast operation, high sensitivity, self-monitoring, low maintenance are the characteristics of the digital/ numeric relays and their cost is also relatively low. Accuracy, flexibility, reliability, multi-functional capability, and working under wide range of temperatures are the advantages of these relays. They have few limitations such as complexity,