The necessity of preliminary estimation of the value of voltage dip arising at starting-up of asynchronous motor commensurate in power with operating diesel-generator sets as part of the ship electric power system is justified. The model of ship electric power system with a modified in real-time mode configuration is developed. The process of direct starting-up of asynchronous motor is simulated, and the values of voltage dips for various values of voltage and time of excitation boost of the synchronous generator are determined. It is established that there are optimum values of the magnitude and time of boosting of excitation voltage of the synchronous generator, where voltage dip in the network is minimal. The obtained results enable assessing in the process of monitoring and management of ship electric power system of the possible consequences of direct starting-up of asynchronous motor on the network voltage under current conditions, and based on them deciding on whether to connect the additional diesel generator to the network or disconnect the least essential consumers of electricity from the network to provide generated capacity reserve. Streszczenie. Zbadano możliwości zapadu napięcia w systemie okrętowtm generatora współpracującego z silnikiem diesla. Symulowano generator asynchroniczny podłączony do sieci dla różnych warunków startu. Określono optymalna wartość napięcia wspomagającego zapewniającą minimalne zapady napięcia. System wyprzedzający sterowania wzbudzeniem generatora synchronicznego umożliwiający zredukowanie zapadów napięcia podczas startu silnika asynchronicznego