DIGITAL DESIGN AND VERIFICATION OF OVER CURRENT RELAY FOR POWER SYSTEM

Abstract

Protective relay is a device which gives instruction to a breaker to disconnect a faulty part of the system. Overcurrent relays are widely used in power system protection. The relay operates when actuating current exceeds the pickup value of the current setting. MATLAB is used to create a testing platform of the relay. The instantaneous relay and inverse time over current relay are designed first in SIMULINK to get the idea of functioning of the relay. A model based design approach has been applied in this dissertation for the development of the power system protection schemes. The motivation behind this approach is to obtain its HDL ( hardware description language ) implementation for rapid system prototyping. This approach highly accelerates the design, verification and implementation of the modern day digital systems. The code generation is done using the simulink HDL coder. The code generation is supported by keeping the hardware specific constraints like fixed point data type in the design during the system development.Instantaneous relay is designed and verified in SIMULINK. After the successful designing of the relay, the required hardware description language code is generated and verified using the test bench. In the present work an over current relay has been designed which is extremely used in power system protection. The digital hardware realization of the designed relay can be obtained from the generated VHDL codes from the SIMULINK HDL coder.