An innovative method to eliminate multiple exponentially decaying DC components based on the discrete Fourier transform in the numerical distance relay

Exponentially decaying direct current (EDDC) components in the faulted of a power system can result an imprecise estimation fundamental frequency component. Because sources such as transmission line, transformer (CT), and relay's internal CT, signals tend to include multiple EDDC components. This paper presents accurate model current, including new term that belongs CT along with line response. Moreover, this proposes innovative algorithm eliminate The feasibility performance proposed were validated using several static, dynamic, experimental tests. static test was carried out MathWorks’ MATLAB® software. For dynamic validation, transient data (simulated commercial PSCAD© software) employed propounded method. performed on distance protective relay manufactured by VEBKO AMIRKABIR Co. main advantages method practical resulting from its simple structure, ability effectively suppress adverse influence (including response CT), accuracy estimating