Power measurement and harmonic analysis of large adjustable speed drives

Details are given of two power electronics adjustable speed drives, (ASDs) that were installed on utility power-plant boiler-feed-pump motors for conversion to speed control. One is a 2250 HP modified load commutated inverter with six pulse input and six pulse output. The other is a current-source inverter with 12 pulse input rectifier and 12 pulse output inverter. The authors show electrical system configuration, input and output current, and voltage wave shapes for each system. Means for measuring power and harmonics in power plant ASD installations using a real-time spectrum analyzer are discussed. ASD efficiency and measured additional motor losses from harmonics as determined in the field are presented.<
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