Challenges of ship propulsion systems during DP operations

Ship propulsion configurations with dynamic positioning systems are commonly used as diesel-electric. In particular, situations for ship transfer on longer distances may be used conventional mechanical propulsion system with controllable pitch propeller. Combination of mechanical and electric propulsion system called hybrid propulsion is met as well, where the thrusters of DP systems are driven through the gear by mechanical engine or electric motor independent or both. For the sake of the necessity of limitation of total installed power on the ship may occurred problems with power distribution between the ship propulsion and industry part. It will especially concern those situations when we need to keep power supply to the industry part and there is a necessity to increase the power delivered to ship propulsion part for the purpose of keeping the ship position or heading. The primary task of power management system (PMS) is blackout prevention in ship energetic network and so power distribution to overcome critical conditions of it. Temporarily it may occur the worsening of positioning operation accuracy without any critical situations of industry part. The possibility of momentary overloading of energetic network is primary condition of safety. The critical duration of overloading is one minute. This is indispensable time for increasing the accessible power in the energetic system through switching on the next genset to work. It is a necessity of quick analysis in critical conditions to value what key-actions ought to do in the aim of overcoming emergency situations. The next one is a usage of energy storage devices. It is possible through AC/DC conversion. It was tried to find solutions of equalization the load of gensets to the ship electric energy demand.