Study on Speed Measurement of Steam Turbine Shaft

Abstract

Speed signal is an important monitoring signal in Steam Turbine Condition Monitoring And Fault Diagnosis(TDM) system. A review on the existing speed measurement methods of rotary machine was proposed to find out the defects of each method. A new approach was introduced to fulfill steam turbine speed accurate measuring. The periods of phase signal pulse generated by the key groove and speed signal pulse generated by the velocimetry gear, were measured respectively by the two independent 16-bit timer/counters, and the "counter overflow" problem was resolved by calling a byte memory unit. According to the record number of the counter, the value of steam turbine speed was calculated accurately. The method of steam turbine speed measurement proposed in this paper can not only simplify the structure of a TDM system, but also reduce its cost.