Automated bus transfer control for critical industrial processes

The techniques and methods for maintaining continuous electrical power to petroleum and chemical facilities from two or more utility feeders by an automated bus transfer logic controller (ABTLC) system are discussed. The purpose of this system is to reduce transients, torsional forces, inrush currents, and motor stress while maintaining continuous motor operation when the primary utility source experiences an interruption, and the operating facility transfers the motor load to an alternative source of electrical supply. The engineering studies, application considerations, motor control design requirements, installation, and operation of the automated bus transfer controller for a chemical facility are presented and discussed. The present bus transfer methods are reviewed. The effectiveness of these methods using typical buses is discussed. The influence of bus voltage and phase angle characteristics during bus transfer for determining the heat transfer technique is also analyzed