A microprocessor-based relay for parallel transmission lines

A digital algorithm for the protection of parallel lines has been implemented with a 16-b single board computer. The relay was tested on a physical model consisting of two synchronous machines connected to a double circuit line. The algorithm is based on the comparison between currents of two circuits. Details of the experimental setup and the test results for various operating conditions are given. The stability of the relay under switching conditions is also studied. Results show the successful operation of the relay.<<ETX>>