Influence of regenerative braking to power characteristics of a gantry crane

The aim of this paper is to present and discuss the results of the power quality measurements that were carried out on the gantry crane which is settled in the container centre of Muuga seaport in Estonia. When lowering the hoist and braking the trolley, the driven motors operate in a regenerative braking mode and feed some active power back into the electrical grid. As the load of a crane varies during each cycle the measurements were carried out in order to analyze the influence of variable energy flow to power characteristics.