An active heave compensation system (AHC) is described in the paper. Active control enables us to compensate vertical vessel motions generated by sea waves. Such systems are used on a special offshore installations and construction vessels, performing the necessary work related to subsea field exploration. The most common AHC systems are based on an application of winches. Among many possible solutions, an electric drive is often used in order to control the speed and the moment, by the application of a frequency converter. The simple control system presented in the paper allows its real-time application on an onboard PC and through a PLC software. The system is implemented and operates currently on an offshore pipelay vessel.SIMULATION OF AN AHC SYSTEM DURING OFFSHORE INSTALLATION
The paper presents an active heave compensation (AHC) system. Active control of the device’s drive system allows for the compensation of vertical vessel motions caused by sea waves. These systems are installed on special vessels designed for offshore installation and construction work, required for the commissioning and operation of subsea oil or gas fields. Most commonly, these systems are integrated into winch systems. Among many possible solutions, the paper presents a drive using electric motors, which transmit the appropriate torque and speed thanks to the use of a frequency converter. The simple control system used in the model allows for the implementation of the system on an onboard computer using a PLC. The proposed compensation system has been built and is currently in use on one of the vessels for laying pipelines on the seabed.
1. INTRODUCTION
Natural resources accessible by onshore-based exploration are more and more exhausted. In order to meet global energy demand, the industry is forced to seek different sources of energy well into the seabed. This applies in particular to oil and natural gas, in some extend also to other materials and minerals. (…)
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Source: Logistyka Magazine
Simulation of an ahc system during offshore installation – PDF file for download