Selection and application of relay protection for six phase demonstration project

The protection and control requirements needed for a 115 kV line after it was reconfigured to operate as a single-circuit six-phase line as part of a high-phase-order demonstration project are discussed. Addressed are the required modification and/or additions needed for the existing protection and control equipment. The criteria selected for the protection of the transmission line are described, including the transformers required for six-phase reconfiguration. The commercially available digital protection systems applicable to the protection of the line and their limitations are reviewed. Requirements for protection and control panels, their location for optimal wiring, and facilities to perform tests and measurements are also covered. >