Modeling and experimental validation of a proposed distance protection system for MVDC transmission lines

Protecting direct current transmission lines (DC-TLs) against faults is challenging and crucial, especially when locating faults. This research aims to develop a novel distance protection approach for Medium voltage direct current transmission lines (MVDC-TLs). Various faults in the computerized experiments and practical models have been applied to the proposed system in the AC network and DC transmission lines to evaluate the performance of the proposed method. The proposed protection system employs the wavelet transforms (WT) and ANFIS as detailed coefficients ‘feature extracting’ tools and classifiers, respectively. The mechanism operation of the proposed method is composed of three stages. Firstly, it extracts the features of the faults by WT. Hence, the ANFIS training process uses such features to identify and classify the faults. The third stage utilizes the ratio value between the fault current and the healthy operation current as an input of another ANFIS model to locate faults on the DC TL. The performance of the proposed protection method has been tested and evaluated for MVDC and MVAC networks. Also, the research executes both practical and simulation experiments utilizing different faults. It examines various fault locations on the entire MVDC line. The mechanism measures the current signals on both sides of the DC-TL. The paper built the MVDC-TLs model and the different cases using the software PSCAD/EMTDC and the proposed method via MATLAB. The study tested faults along the TL in the presence of the AWGN noise. The research utilizes practical experiments to verify the accuracy of the proposer. The accuracy of the proposed fault location is 99.923 %. Based on the results of this research paper and comparison with the recent related research works, the proposed method is more effective and efficient than the previous methods in detecting, classifying, and locating system faults.