A Complete Electrical System Study for a Refinery With Major Expansion

A full electrical system study for a large refinery with major expansion is reported. The expansion added two new gas turbine generators (GTG) as well as one new steam turbine generator (STG) to the system. A gas-insulated switchgear (GIS) lineup was installed at the 22 kV main substation with a new current limiting reactor to tie the main buses. Four of the substations are new as part of the expansion to increase the total number of substations to fourteen. Due to the new generators, a complete system study to size equipment, adjust protection settings, verify operating conditions and ensure system stability was carried out. The system study scope includes load flow, short circuit, protection and coordination, motor starting, and transient stability. The project lasted and covered the entire construction stages from For Review (FR) and For Design (FD) to For Construction (FC). The detailed system study helped the construction contractor and refinery owners to validate system design, confirm operation procedures and finalize protection schemes under both normal and abnormal conditions. Further, this paper shares experiences gained from performing and managing a complete system study project for an industrial facility in after front-end engineering design (FEED) phase in terms of validating system models, selecting study scenarios, leveraging computer software features, analyzing study results and proposing recommendations.