The distribution of currents and voltages in a short ring transmission system

This paper presents a study for the ring transmission systems on the basis of equivalent circuit. The mathematical analysis for voltage, current and power including the effect of variations of the load is deduced. The change of a load has been classified according to either value or angle. The group of mathematical equations is programmed and processed. The effect of ring impedance type on currents through and voltages at terminals of both first and second circuits of the studied ring system is considered. The dependence of the distribution of currents through the three (first, ring, second) circuits of the proposed system is investigated. The type of a load is firstly included according to the dependence on its angle. This load is simulated as a symmetrical impedance for all phases during the research. Its variations relative to power factor angle should be calculated. The transmitted power due to the change of the load is computed and the results are discussed. Both active and reactive powers are considered and then the deduced results are given and analyzed. The effect of the ring impedances as capacitive is also included. The transmission efficiency is driven and the advantages of the suggested system are discussed. Also, the higher voltages produced at some points in the capacitive ring type leads us to propose a commutative capacitive and inductive impedances for the ring part of the studied system, where this condition is taken into consideration. This work and the results herein are a great development and a good improvement on the performance of the ring transmission system. The appeared ring system in a symmetrical sequence has been encouraged. Also, the effect of place of connection of the proposed ring bank is investigated for different locations along the line such as 1/4, 1/2, 3/4 of the line length and finally at the receiving end. The effect of load power factor on the distribution of node voltages and branch currents as well as on both active and reactive powers along the proposed new bank ring system have been worked out and analyzed. The voltage ratio is computed and given. (C) 1998 Elsevier Science S.A. All rights reserved.