Performance of a Short Transmission Line Module under Various Loads

A Comparative Evaluation

Abstract

A Short Transmission Line (STL) module was designed and implemented. There had been a serious need to have such a module in the electrical power laboratory of Auchi Polytechnic in order to satisfy the National Board for Technical Education (NBTE) practical coverage requirement, especially as affecting experiments on transmission lines. In this paper a presentation is made of the development of the STL module by the selection and use of relevant discrete components. Concerning the module inductance, four panel inductors were selected and connected in series to give an inductive unit rated 14.89mH, 5.77A, at 50Hz and 27V voltage drop, as realized from ammeter-voltmeter test. For the module resistance requirement, eight industrial resistors were selected (each rated 7.98Ω, 24W) and were connected in parallel to realize an effective resistance unit of about 1Ω. And a dedicated rheostat of 4.81Ω, 10A rating was selected for the purpose of line loss variation exercise. The laboratory results obtained and the computations for the STL module ABCD constants and other parameters were seen to reflect clear differences in ten key parameters sequel to variation in load power-factor. It was concluded that using this module will demonstrate to students the adverse effect which poor load power factors have on the performance of short transmission lines, thus highlighting the advantage of power-factor correction. It was also clear that the module will demonstrate to students the higher generation cost involved in sending electrical power to low power-factor loads.