Analysis of Switching Overvoltages in Ships Electric Power System

Ships electric power systems can work in different regimes. They usually works in normal work regime in which needs of all customers are fulfilled with values of frequency, voltages and other characteristic variables deviations in ranges defined by regulations. Transitions of regimes can be spontaneous (as consequence of some unpredictable events such as failures, environment influences and so on) or by purpose (as consequence of dispatching operations). They cause transient processes because system consists of differently connected oscillatory circuits. The transient processes can trigger of high values of voltages, so called inner overvoltages. High voltages can be very dangerous for insulation of electrical equipment. The causes for the appearance and existence of the different types of inner overvoltages and their consequences are numerous and different, and therefore special attention should be paid to them by means of power system reliability and security. Switching overvoltages are one of inner overvoltages. This type of overvoltages is caused by breaker's commutation in the cases of normal regime or in the cases of failure. Due to large number of influencing parameters, calculation of these overvoltages is very complex, and exact results demand application of advanced computer programs. The possibility, which can make the calculations and analysis of switching overvoltages originated by different causes faster and easier by using relatively simple, but exact enough, derived mathematical method and computer application, will be presented in the paper. Calculated results will be used for the analysis of the advantages and disadvantages of the pro posed procedure and for validation of the introduced improvements.