Transformer Sympathetic Inrush Effect on Radially Fed Off-Shore Oil Production Platforms: A Case Study

Electrified oil platforms are becoming predominant in the oil and gas industry for offshore production. Large transformers and long submarine cables are being utilized to ultimately supply power to electrical submersible pumps (ESPs). Consequently, detailed analysis is required to study complex phenomena, including switching transients associated with transformer and cable energization. This paper presents a case study for the impact of transformer energization on system voltage for radially fed power network. In the case where multiple transformers share the same primary bus, the switching transients associated with one transformer energization causes a voltage sag affecting the loads connected to the other adjacent transformers. The sag is attributed to a sympathetic inrush phenomenon experienced by the moderately loaded transformers sharing the primary bus with the transformer being energized. The authors conducted field measurements using power quality recorders, and built a power system model to reproduce the field results using commercially available transient modeling software. Remedial solutions were studied to alleviate the impact of transformer energization on system voltage.