Performance and Test Criteria for DC Fuses in Coal Mine Applications

A comprehensive study was made of dc system parameters in coal mines to recommend performance and test criteria for dc fuses. Field tests were conducted in ten coal mines in which transients were initiated on the dc system from which the parameters of the dc mine electrical power system could be determined. Data processing was done to fit an exponential curve to the field waveforms. From this data analysis finding the dc system resistance, inductance, and time constant was possible. A survey of nationally recognized laboratories was conducted to establish that the recommended test criteria were practical. The development of test criteria for dc fuses used in mines was based on the measurement of parameters in the field, the survey of testing laboratories, literature searches, and laboratory tests. Methods to predict analytically the parameters measured in the field are discussed. A brief laboratory testing program was carried out to verify the practicality of the recommended criteria.