Floating, Production, Storage, and Offloading Unit: A Contingency Operating Mode Using Variable Frequency Drives

Abstract

With the current utilization of Floating, Production, Storage, and Offloading (FPSO) units by the petroleum industry, and the trend towards optimizing the energy efficiency of electrical systems, Variable Frequency Drives (VFDs) play a crucial role in enhancing the performance and power quality (PQ) of the power system on these offshore platforms. The FPSO unit operates in various modes, depending on its regular activities, such as contingency, production and offloading. Each operating mode has multiple grid configurations with different generation and load connections, including the contingency mode that is used for planned maintenance or failure in one of the aeroderivative gas turbine generators (GTGs). During the contingency mode, the FPSO unit runs with two GTGs and implements load shedding. Therefore, this paper investigates a specific case of the contingency operating mode, considering scenarios with zero, one, two, and three VFDs connected to the largest motors. Additionally, it analyzes VFDs with both passive and active frontend rectifiers, aiming to minimize the number of loads to be shed during contingency. The main result shows that by using the active front-end VFDs, 14.3 MW of loads that would be shut down during contingency mode can continue to operate.INDEX TERMS Energy efficiency, oil and gas platform, power factor, reactive power control, variable frequency drives.