Case study on the effectiveness of condition monitoring techniques for fault diagnosis of pumps in thermal power plant

Caneon Kurien,Ajay Kumar Srivastava

doi:10.2478/mme-2019-0010

Abstract

Abstract A case study was carried out to investigate the effectiveness of condition monitoring techniques in the early failure detection of pumps in a thermal power plant. Various condition monitoring techniques used in this case study involved vibration analysis, motor current signature analysis, noise monitoring and wear debris analysis. These techniques were applied on the three pumps, namely boiler feed water pump, auxiliary cooling water pump and condensate extraction pump, which have to work continuously for the operation of the thermal power plant. Vibration analysis of the auxiliary cooling water pump showed that there is a rising trend in the acceleration values at its driving and non-driving end indicating the deterioration of bearings. Motor current index range of all the pumps was found to be within acceptable limits. Wear debris analysis of lubricant in the hydraulic coupling of boiler feed water pump indicated the presence of sand, dirt and low alloy steel sliding wear particles in it. Condition monitoring techniques have been proved to be an effective technique in early failure detection of pumps.

Highlights

Condition monitoring is a maintenance technique for the diagnosis of defects in machineries, while it is in working mode so that its operation will not be interrupted [1]
Various condition monitoring techniques used in this case study involved vibration analysis, motor current signature analysis, noise monitoring and wear debris analysis
Effectiveness of condition monitoring techniques in the early failure detection of pumps in thermal power plants has been studied in detail

Summary

Introduction

Condition monitoring is a maintenance technique for the diagnosis of defects in machineries, while it is in working mode so that its operation will not be interrupted [1]. The amplitude is expressed in terms of displacement, velocity and acceleration depending upon the frequency and operating speed of the machinery [7]. When the operating speed ranges from 600 to 60000 rpm, the vibrations are expressed in terms of velocity, since it is developed under conditions of fatigue. In cases when higher frequencies are produced by forces and the speed is above 60000 rpm, vibrations are measured in terms of acceleration [8]. Motor current signature analysis (MCSA) involves the monitoring of current in the induction motor by the analysis of the current spectrum for spotting the fault frequen-

Before After

Motor current

Conclusion