Standardization of Benchmarks for Protective Device Time-Current Curves

The history of time-current curves and the development of time-current curve techniques and practices leading up to the present day standards are reviewed. A format is suggested for the calculation and illustration of benchmarks on time-current curves. The discussion will encompass medium-and low-voltage coordination benchmarks as well as the identification of time-current curve elements. A brief discussion of time-current curve production using computer graphic techniques is also included.