In this paper, the task was to describe the basic features of the medium-voltage shipboard electrical power system used on large ships with electric propulsion. In fact, these are voltages above 1000 V, which are high voltages for ship applications with an upper limit of 15 kV. In the second chapter, we gave a general overview of the functioning of the shipboard electrical power system, and in a separate subsection, we explained the reason and method of introducing high voltage, as well as its basic characteristics. The third chapter shows several typical schemes of shipboard high-voltage electrical power systems. The fourth chapter describes the basic energy sources, typical generators used on ships, and emergency power sources used when primary energy sources are disabled. The fifth chapter provides an overview of systems and devices for energy distribution and transmission, from electrical networks, through transformers and switchboards to types of converters. In the sixth chapter, we presented the basic features of electric propulsion and the types of motors used, from motors directly connected to the grid, motors with variable speed. We also described the latest concepts of electric propulsion, azimuth thrusters and pod propulsion. The seventh chapter talks about consumers of electrical energy, primarily about electric drives, which are the main consumers of energy at the medium voltage level. Since any contact with high voltage can be fatal, special attention should be paid to safety procedures to protect the devices in the first place from ground faults, and the personnel working with these devices. This was discussed in the eighth chapter.