Power Factor Correction Capacitators: Upgrading a Refinery's Transformers to Deal with Increased Load

As a result of a major revamp and several expansion projects to a 30-year-old world-class petrochemical refinery, the total refinery power demand increased from 67 to 100 MVA with a corresponding lagging power factor (PF) decrease from 93 to 89% at the 34.5-kV system. The refinery has a secondary selective system and gets its power from the utility company via two main power transformers. Each transformer is rated 60/80/100 MVA oil: natural, air: natural (ONAN)/oil: natural, air: forced (ONAF)/oil: forced, air: forced (OFAF) with a 115-kV primary and a 34.5-kV secondary. The latest expansion project was committed to reserve at least 10 MVA in each transformer for future growth in a single-ended condition while supporting the total refinery load.