International Journal of Research and Scientific Innovation (IJRSI) | Volume V, Issue IV, April 2018 | ISSN 2321–2705

An Overview of Steam Turbine Blade Vibration Monitoring System (BVMS)

Pratik Dalvi1, Devidas Barge2, Hrishikesh Dhandha3

  ^{1, 2, 3}Department of Mechanical Engineering, Datta Meghe College of Engineering, Airoli, Navi Mumbai, Maharashtra, India

Abstract- This paper describes an overview of blade health monitoring system used for steam turbine. Alternative of conventional blade vibration measurement system, a non-contact measurement technique is investigated. The blade vibration can be detected by measurement of tip timing since the blade timing will slightly differ from the passing time calculated from the turbine rotor speed in the presence of the vibrations. The operation of blade vibration monitoring system and the components required for its operation has been presented. Vibrations of last stage free standing blades of low pressure steam turbine can cause high cycle fatigue, which damages the blades and reduces blade life. The operational risks associated with high-cycle fatigue failures as well as other failure like stress corrosion cracking, blade root failure etc. can be observed by using non-contact type monitoring system known as Blade Vibration Monitoring System.

Keywords- Steam Turbine, Vibration Measurement, Blade Vibration Monitoring System, Turbo-machine, Optical Sensors, Condition Monitoring, Data Acquisition.

I. INTRODUCTION

The Steam turbine consist various components, blades are especially important among all. While rotating, turbine blades experience vibration which generate stress and cause the damage of the system. The blade vibration amplitude and frequency have a profound impact on integrity, operations, performance and fatigue life. The accurate estimation of blade vibration is crucial issue. The various incrementing technologies are being discuss related to blade vibration measurement, damage signatures, and monitoring system for all blades.

Continuous availability of steam turbine in a power plant directly related to its performance under distinct operating conditions. In the recent past Low Pressure Turbine free standing stage blades failure experienced in many of large capacity steam turbines. Statistics shows that LP Turbine free standing blades are more susceptible to failure compared to those of HP & IP Turbine blades.