FIRST ZONE PROTECTION SCHEME FOR TRANSMISSION LINES

Abstract

Protection scheme in a transmission lines is essential to determine abnormal conditions and protect a healthy system from that particular abnormal conditions. Digital protection schemes are nowadays very much advantageous as compared to the analogue relays. A large degree of freedom is allowed in digital protection scheme with respect of cost, reliability and flexibility. By accurate implementations of different filtering and electrical signal processing algorithms as relay logic, fast, accurate and flexible protection scheme can be achieved. In this whole work implementation of new algorithms and modification work of previously defined algorithms has been done to get an improved protection scheme by determining fault type and location of fault. Diagnosis of faulty line requires accurate detection of the line where fault has occurred. This operation has been performed here by using by Fuzzy Fault Classification Scheme, Batch Least square algorithm and Gradient method. Detected faulty line has been treated with Least Square Error Technique to achieve exact location of fault to properly execute first zone protection. Fuzzy Fault Classification has given an awesome result to in case of detection. Batch Least Square algorithm and Gradient method can give a way to predict outputs by automated fuzzy logic in the field of protection with further enhanced implementation. Least Square Error algorithm executes efficiency near 100% in case of calculating location of fault for all the three types of fault. Simulation of faulted transmission line has been performed with PSCAD/EMTDC software and more than 1000 fault cases of different transmission line length have been treated. Result obtained from the MATLAB coding of that algorithm, has found very accurate to determine that the fault has been occurred in between first zone or not.