How do you manage the power and thruster allocation in a DP system?

1 DP system design and redundancy

A DP system consists of three main components: the DP controller, the power system, and the thruster system. The DP controller is the brain of the system, which receives inputs from sensors, reference systems, and the operator, and calculates the required thruster forces and moments to maintain the desired position and heading. The power system is the source of energy for the thrusters, which can be diesel generators, batteries, or shore connections. The thruster system is the set of propellers, azimuth thrusters, tunnel thrusters, or other devices that generate the thrust. A DP system should have enough redundancy to cope with failures or faults in any of these components, without compromising the safety or performance of the vessel. This means having multiple independent subsystems, backup modes, and emergency procedures.

2 Power and thruster demand

The power and thruster demand of a DP vessel depends on several factors, such as the environmental conditions, the vessel characteristics, the operational requirements, and the DP class. The environmental conditions include the wind, waves, currents, and ice, which exert forces and moments on the vessel that need to be counteracted by the thrusters. The vessel characteristics include the size, shape, weight, and hydrodynamic properties of the hull, which affect the drag and inertia of the vessel. The operational requirements include the position and heading accuracy, the speed and maneuverability, and the station-keeping or tracking modes of the DP operation. The DP class is the level of redundancy and reliability of the DP system, which determines the number and type of thrusters, power sources, and controllers that are needed.

3 Power and thruster optimization

The power and thruster optimization process seeks the best allocation of power and thruster forces and moments to meet DP objectives while minimizing fuel consumption, emissions, noise, wear and tear, and risk of failure. To achieve this, there are various methods and tools available, such as the power management system (PMS) for monitoring and controlling power generation and distribution, the thruster allocation logic (TAL) for calculating and distributing thruster commands from the DP controller to individual thrusters, optimization algorithms for finding optimal or near-optimal solutions based on criteria and constraints, and simulation tools for testing different scenarios and configurations to assess the performance of the DP system.

4 Power and thruster monitoring

The power and thruster monitoring process involves observing and analyzing the power and thruster status, performance, and behavior during the DP operation. It is important to monitor a range of power and thruster parameters, such as the power consumption, generation, and balance which indicate the efficiency and stability of the power system; the thruster forces, moments, speeds, and angles which indicate the effectiveness and accuracy of the thruster system; as well as the thruster loads, temperatures, pressures, and vibrations which indicate the condition and health of the thruster components. Through monitoring these parameters, it is possible to identify and diagnose problems, optimize settings, prevent accidents, and improve performance.

5 Power and thruster training

Power and thruster training is essential for DP operators, engineers, technicians, and managers to acquire and update the knowledge and skills related to power and thruster management in a DP system. Training can be done through theoretical courses which provide background information, concepts, and theories of the power and thruster systems. Practical exercises give hands-on experience, practice, and feedback of the power and thruster systems using simulators, models, or real vessels. Certification programs provide formal recognition, qualification, and accreditation of the power and thruster competencies according to industry standards and regulations.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?