Reduction of Overvoltages under Connection on a High-Voltage Cable Line Due to Optimal Controlled Switching

The purpose of the work is to develop a mathematical model of a cable transmission line, which allows modeling and choosing the optimal conditions for controlled switching to limit overvoltage at the development and design stage. The goal is achieved by solving the problem of determining the initial angle of each phase, so that each phase has an initial switching angle equal to zero with a time delay. A high-voltage cable line for a voltage of 330 kV, implemented using Matlab, has been chosen as the object of study. The most significant result is the method of numerical simulation of the cable line that allows you to analyze transients when each phase of a three-phase cable line is connected to a three-phase source with a time delay, the switching angle of all phases is zero. This, in turn, makes it possible to limit switching overvoltages. The significance of the results obtained lies in the possibility of the proposed technique to choose the optimal conditions for controlled switching, which makes it possible to use it in the design of switching nodes, as well as the use of controlled switching to eliminate unwanted electrical transients during planned switching. The simulation results showed that the greatest effect of using numerical simulation is when each phase of a three-phase cable line is connected to a three-phase source with a time delay of 1/150 second, then the switching angle of all phases is zero, which makes it possible to limit switching overvoltages. Keywords: three-phase cable line, switching overvoltage, transient processes, controlled switching, theory of multipoles, modeling of electrical engineering objects.