The refrigerated container ship with AC440 V main distribution network cannot achieve the maximum loading capacity of the reefer container during the handling of the reefer containers at port or must turn on the main generator for power supply, due to the maximum capacity limitation of 6 300 A for the AC440 V air circuit breaker (ACB) and the limited capacity for the 4 800 kVA single step-down transformer. In the current study, the power can be supplied independently on both sides of the low-voltage main distribution board by adding one output panel on the traditional high-voltage shore power change-over panel and a step-down transformer to the main circuit. The capacity limitations of the ACB and the step-down transformer can then be solved to maximize the total capacity of the shore power system and achieve automatic safety interlocking protection and operation process guidance. It can effectively improve the safety of ship operation and economic benefits.

Polar navigation is the guarantee for ships to achieve scientific research and safe navigation in the polar area. At present, there are many studies on the theory of polar navigation in China about the arrangement of Inertial Navigation System (INS), the availability of satellite navigation polar area, multi-sensor integrated navigation, etc. But there are still blanks in the application of polar navigation and ice exploration equipment in the high latitude navigation engineering in the polar area. In order to solve the engineering application problems of the device in the polar region from the system level, the paper combines the theory to analyze the polar environment and ship based in the polar region on the performance of the navigation device, and combines the research status of the ice exploration radar, inertial navigation, satellite navigation, electronic charts, satellite communication and other devices in the polar region, studies the working process of the design of the ice navigation device, and discusses the direction of future research and development of the navigation device in China.

The development of heavy icebreakers above PC2 class has become an important part of the polar strategy with the growth of the demand of polar exploration research and development in China. A propulsion system with great power and redundancy is a particular feature of heavy icebreakers. It is found that the electric propulsion system has become the development trend through the analysis of the foreign heavy icebreakers using conventional power. The total capacity of its integrated power system is often greater than 50 MW. The output power of the propulsion motor can reach 20 MW with multiple main thrusters, and the single engine power may exceed 10 MW with more than four prime motors. The capacity level of the above-mentioned key devices of the power system is rarely used on existing ships, with insufficient domestic supporting parts. The essential parts of the power system such as the generators, propulsion motors and frequency converters are selected by analyzing the power grid voltage level based on the demand of heavy icebreakers. Combined with the domestic supporting situations, a power grid architecture for the heavy icebreaker is proposed with reference to the existing power grid architecture in foreign countries, in order to facilitate the development of subsequent ships.