On-line utility tie power factor control

Large industrial operations with internal electrical generation capabilities and parallel utility ties have always worked to control watt and VAr flows across their tie lines. In today's economic climate, the ability to control tie line operation can significantly impact a facility's bottom line. In a power system expansion, Union Camp Corporation's Savannah pulp and paper mill installed a tie line power factor control system that has proven to be reliable and effective. It uses load tap changers on two pairs of utility tie transformers to maintain control within the guidelines of the utility contract. It is implemented by a programmable logic controller (PLC) and other nonproprietary hardware. An analysis of this project illustrates how this scheme can be implemented on simple or complex power systems.