Active power filtering solution for improving power quality in cold ironed electric ships

Abstract

Climate change is always a concern in the shipping sector, and there is a constant effort in the international shipping community to reduce greenhouse gases (GHG) emissions. The public transportation and commercial vehicle sectors have already begun implementing electric vehicles to meet the emission reduction requirements that are being put in place around the world. It is time that the commercial shipping sector joined them by working towards the electrification of ships and possibly using large batteries as fuel. However, there are some concerns with the ability to charge batteries during long voyages and the weight addition that large batteries would bring. One way to reduce GHG emissions in port is by cold ironing a ship or plugging in a ship to an onshore power source instead of using onboard diesel generators when ships are at port. This is effective because the main propulsion does not need power while in port. However, to ensure that the integrity of the onshore grid is not affected by this additional heavy load that may arise from the loads onboard the vessel, these loads must be analyzed before connecting them to the onshore grid. In this paper, to address these issues, this paper aims to investigate the power quality of the distribution side of T/V General Rudder, a Texas AM University Galveston's owned ship. Based on the distribution system's harmonics content and power quality, the authors propose an active filter on the secondary side to reduce the Total Harmonic Distortion (THD). The proposed filter results in a decrease of 90% total harmonic distortion, leading to increased efficiency and system performance. Further, the impact of load on the onboard diesel generator and the onshore electrical grid is also examined.