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EPRI Technical Report TR-108935

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  • Infrared Thermography AnomaliesManual TR-108935

    Final Report, August 1997

    Prepared byEPRI Monitoring & Diagnostic Center#3 Industrial HighwayEddystone, PA 19022

    AuthorsS. BradenB. HammakerB. Woyshner

    Prepared forElectric Power Research Institute3412 Hillview AvenuePalo Alto, California 94304

    EPRI Project ManagerR. PflastererGeneration

    Effective December 6, 2006, this report has been made publicly available in accordance withSection 734.3(b)(3) and published in accordance with Section 734.7 of the U.S. ExportAdministration Regulations. As a result of this publication, this report is subject to only copyrightprotection and does not require any license agreement from EPRI. This notice supersedes theexport control restrictions and any proprietary licensed material notices embedded in thedocument prior to publication.

  • DISCLAIMER OF WARRANTIES AND LIMITATION OFLIABILITIESTHIS REPORT WAS PREPARED BY THE ORGANIZATION(S) NAMED BELOW AS AN ACCOUNT OF WORKSPONSORED OR COSPONSORED BY THE ELECTRIC POWER RESEARCH INSTITUTE, INC. (EPRI). NEITHEREPRI, ANY MEMBER OF EPRI, ANY COSPONSOR, THE ORGANIZATION(S) BELOW, NOR ANY PERSON ACTINGON BEHALF OF ANY OF THEM:

    (A) MAKES ANY WARRANTY OR REPRESENTATION WHATSOEVER, EXPRESS OR IMPLIED, (I) WITH RESPECTTO THE USE OF ANY INFORMATION, APPARATUS, METHOD, PROCESS, OR SIMILAR ITEM DISCLOSED IN THISREPORT, INCLUDING MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, OR (II) THAT SUCH USEDOES NOT INFRINGE ON OR INTERFERE WITH PRIVATELY OWNED RIGHTS, INCLUDING ANY PARTY'SINTELLECTUAL PROPERTY, OR (III) THAT THIS REPORT IS SUITABLE TO ANY PARTICULAR USER'SCIRCUMSTANCE; OR

    (B) ASSUMES RESPONSIBILITY FOR ANY DAMAGES OR OTHER LIABILITY WHATSOEVER (INCLUDING ANYCONSEQUENTIAL DAMAGES, EVEN IF EPRI OR ANY EPRI REPRESENTATIVE HAS BEEN ADVISED OF THEPOSSIBILITY OF SUCH DAMAGES) RESULTING FROM YOUR SELECTION OR USE OF THIS REPORT OR ANYINFORMATION, APPARATUS, METHOD, PROCESS, OR SIMILAR ITEM DISCLOSED IN THIS REPORT.

    ORGANIZATION(S) THAT PREPARED THIS REPORTEPRI Monitoring & Diagnostic Center

    ORDERING INFORMATIONRequests for copies of this report should be directed to the EPRI Distribution Center, 207 Coggins Drive, P.O. Box 23205,Pleasant Hill, CA 94523, (510) 934-4212.Electric Power Research Institute and EPRI are registered service marks of the Electric Power Research Institute, Inc. EPRI.POWERING PROGRESS is a service mark of the Electric Power Research Institute, Inc.

    Copyright 1997 Electric Power Research Institute, Inc. All rights reserved.

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    REPORT SUMMARY

    Infrared thermography (IRT) is non-intrusive diagnostic technique that can play animportant role in predictive maintenance programs. This manual shows how IRT canbe applied in the field to detect anomalies in a wide-range of power plant systems. Thisactivity is part of EPRIs Plant Maintenance Optimization development efforts underTarget 43, Turbine, Generator and BOP O&M Cost Reduction (1997), and Target 54,Plant Maintenance Optimization (1998), which are intended to help utilities reduce thecost of production by developing and demonstrating cost-effective maintenancemethods.

    BackgroundMost of the equipment found in a typical electric generating station exhibits some typeof abnormal thermal pattern prior to failure. IRT is a non-invasive diagnostic techniquethat can detect abnormal thermal patterns by making simultaneous temperaturemeasurements of multiple points on the surface of a piece of equipment. These data aredisplayed as pictures, commonly referred to as thermograms, that can be analyzed inreal-time or stored electronically and analyzed later. Information from thermogramscan be used by electric utilities to plan maintenance and avoid catastrophic equipmentfailures and unscheduled downtime.

    ObjectiveTo provide a guide to the use of comparative infrared thermography to monitor thecondition of power plant equipment.

    ApproachThe project team drew on the experience of thermographers at EPRIs Monitoring &Diagnostic Center to produce a manual on the application of IRT to the examination ofpower plant equipment.

    ResultsAfter a brief introduction to the technical background IRT, the manual describes howinfrared thermography can be used to detect thermal anomalies in power plantequipment. The thermal anomalies illustrated in this document include stationelectrical applications, rotating equipment applications, transmission and distributionapplications, and performance applications. Some of the cases are analyzedquantitatively, while others are analyzed qualitatively. Most of the cases feature a

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    thermal image that is accompanied by a corresponding visual image. An arrowsuperimposed on the visual image allows the reader to match locations on the visualimage with the corresponding locations on the thermal image.

    The information contained in this document was acquired while using IRT to identifypotential problems in the field. In each case feedback was received from maintenancepersonnel involved with repair work as to the as found condition of the equipment.This feedback helps refine diagnostic technique and should be an integral part ofpreventive maintenance. All detected anomalies should also be reinspected with IRTafter repairs are completed to verify that the problem has been corrected.

    EPRI PerspectiveEPRIs Monitoring & Diagnostic Center was established to demonstrate the value ofdiagnostic monitoring and the importance of networking diagnostics to plantmaintenance, controls, and operations. The Centers primary objectives are to validate,improve, integrate, and network diagnostic technologies, to develop programguidelines, and to transfer the technologies to the utility industry.

    TR-108935Interest CategoriesFossil steam plant performance optimizationFossil steam plant O&M cost reductionState-of-the-art power plants

    Key WordsInfrared thermographyNon-destructive evaluationPredictive maintenance

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    ABSTRACT

    Infrared thermography (IRT) is a non-invasive diagnostic technique that utilizesinfrared sensors to make simultaneous measurements of multiple points on the surfaceof a piece of equipment. Most of the equipment found in a typical electric generatingstation exhibits some type of thermal pattern prior to failure. Infrared thermographyprograms are implemented in generating stations as part of a comprehensive PredictiveMaintenance (PdM) program that involves various types of diagnostic tests. Thismanual, based on experience accumulated at EPRIs Monitoring & Diagnostic Center,shows how infrared thermography can be applied in the field to a wide range of powerplant applications.

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    CONTENTS

    1 INTRODUCTION...................................................................................................................... 1-1

    2 IRT TECHNICAL BACKGROUND......................................................................................... 2-1How to Read a Thermal Image................................................................................................ 2-1Comparative Thermography .................................................................................................... 2-2

    A Quantitative Analysis of Thermal Image #1 using Comparative Thermography ............. 2-2A Qualitative Analysis of Thermal Image #2 using Comparative Thermography ............... 2-4

    3 FIELD APPLICATIONS OF IRT.............................................................................................. 3-1Station Electrical Applications.................................................................................................. 3-1

    High Resistance Connection (QT) ...................................................................................... 3-2Stranded Conductor (QT) .................................................................................................... 3-3Defective Thermal Overload (QT) ....................................................................................... 3-3Open Conductor (QT).......................................................................................................... 3-4Defective Fuse and/or Connection Problem (QT)............................................................... 3-4480 Volt Bus Bar and Stab Problem (QT) ........................................................................... 3-54160 Volt Breaker Disconnect (QT) ................................................................................... 3-5Defective Current Transformer (QT) ................................................................................... 3-6Electrical Bus Duct Problem (QT) ....................................................................................... 3-7Ground Strap Connection (QT) ........................................................................................... 3-8

    Rotating Equipment Applications ............................................................................................. 3-9Motor Filter Problem (QT) .................................................................................................. 3-10Motor Bearing Problem (QT).............................................................................................. 3-11Boiler Feed Pump Bearing Problem (QT).......................................................................... 3-12Motor Stator Winding Short (QT) ....................................................................................... 3-13Coal Pulverizer Mill Gear Problem (QT)............................................................................ 3-13

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    Dry Vacuum Pump Cooling Water Restriction (QT) ..................