SIMULATION OF FAULT TRANSIENTS IN CASCADE CONNECTED OVERHEAD LINE/CABLE SYSTEMS

During any fault, transient currents and voltages take place on power transmission system. It is important and desirable to be able to predict the possible occurrences of such overvoltages and overcurrents at the design stage so that the consequent damage to the power-system equipment can be avoided and optimum economical design can be met. In most cases, maximum short-circuit fault overcurrents and overvoltages arise with the occurrence of single phase to earth fault. Therefore, in this paper, this type of fault is studied for the case in which the transmission system is fed from the line end and the cable end. Magnitudes and waveforms of the transients are obtained at three different locations i.e. at sending bus bar and receiving end bus bar as well as at the junction point of the overhead line/ cable system. when the short circuit fault occurs on overhead line, on cable as well as on the junction point. The effects of various factors upon the transient overvoltages and overcurrents arising in the system are investigated, For example, the effects of source location and fault location are all studied.