Improving the Operating Speed of the Distance Protection Scheme of an 11 kV Distribution System using Microprocessors
Authors: Oputa, O., Diyoke, G.C., Onwuka, I.K., Ezeonye, C.S., Abunike, E.C. And Obi, P.I.
DOI Info: http://doi.org/10.5281/zenodo.12599861
ABSTRACT
Distance relays and protection schemes are used in the protection of transmission and distribution lines. The speed of isolating faulty circuits from the network is relatively low and this operation speed was improved in this paper by using a microprocessor to make fast tripping decision for the relay. The microprocessor was programmed by using results obtained from fault studies carried out on the network. Using simulations in Power System Computer Aided Design (PSCAD) software, for a line-to-line (LLG) fault between lines A and B to ground (AB-G) occurring at 35 km on the tested line having a fault impedance of 5 Q, the operating time of the developed system was 5.4 ms whereas it was 15 ms with the old system without the microprocessor (the conventional distance relay system). The new protection system working with the microprocessor was found to have improved the average operating speed of the distance protection scheme from 6.144 ms to 4.390 ms resulting to an improvement of the operating speed or speed of isolating faulty circuit by approximately 29%.
Affiliations: Department of Electrical/Electronic Engineering, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria.
Keywords: Improvement, Operating Speed, Fault Type, Fault Impedance, Distance Protection, Microprocessor
Published date: 2024/06/30
