PARALLEL OPERATION OF H. V. A. C. AND H. V. D. C. TRANSMISSION LINES

Abstract

The analysis carried out here evaluated the effect of d.c. line on the system's transient stability when it is operated in parallel with an a. c. line connecting two synchronous systems. The swing curves of the system are calculated and plotted with the help of point by point methods when unbalanced faults are considered to occur in the middle of the a.c. transmission line* The effect of no control and faster control of the d.c. line on the transient stability and the contribution of the faster control of the d1a. transmission line on the improvement of the transient stability has been investigated. The types of fau t,• selected are 2•►Lw•G and 1.•L••G fault. The currents on the a. c. side of the converter are derived by the Fourier•s series analysis. The expression for the 1 L.G , 2-L-G and 2•L fault ~r are solved with the help of symmetrical component theory. Three itterative steps have been developed to simulate the entire system on IH 7044 digital Computer.