Lesson 131 of Industrial Engineering ONLINE Course.
Process Industrial Engineering Module - Inspection Operations Analysis and Improvement Sub-Module of IE ONLINE Course.
Inspection Activities - Operation Analysis - Process Improvement - Inspection Operations Improvement is a Neglected Area in Industrial Engineering
In IE curriculums, statistical quality control was taught but not the basics of improvement of inspection procedures. The basic drawback in IE curriculums is that the process improvement procedure was not given the adequate focus and development. In many institutes process charts are discussed as part of motion and time study. Even when the subject is renamed work systems design, the content discussed is still the content of "motion and time study". This fundamental drawback of IE needs to be corrected by properly implementing the three steps of outlined in IE definition - Design, Installation and Improvement.
What are the design areas that IE has to concentrate to understand and design?
What systems are to be installed by IEs with active involvement? In what systems installation, they have to play as assisting role?
What systems are improved by IEs? How? The process and system improvement is the core of IE. The redesigned processes and systems are to be installed. To redesign a process or a system, IE have to understand the basic design methodology and followed and they have to identify opportunities for improvement as various points of time based on new engineering developments and creative thinking breakthroughs based on systematic investigation of all elements with a view to finding improvement opportunities.
Inspection is an elaborate procedure with many steps at various points in the process of manufacturing parts, assembling subassemblies, final assembly, and doing various adjustments to get the specified output from the product.
The information given in this note by a third party inspector of transformers gives an idea of the quantum of work involved in inspection. The list is created to identify industrial engineering improvement activities in the inspection activities of transformers. Can you point out any improvement in the inspection activities of transformers?
Industrial engineers have to give adequate attention to inspection operations plans and their analysis based on the plans and actual observation in the shop floor followed by development of process charts and operation analysis sheets.
Third Party Inspection for Power Transformer - Procedure
Picture Source: https://the-rsgroup.com/the-1000th-power-transformer/
The Third Party Inspection for power transformer given below is a sample procedure for power transformer inspection and power transformer testing in the manufacturing shop.
https://www.inspection-for-industry.com/third-party-inspection-for-power-transformer.html
The documents to be submitted to the third party inspector
Power Transformer Purchase Order or Contract
Power Transformer Manufacture Quality Control Plan
Power Transformer Inspection and Test Plan
Power Transformer Data Sheet
Power Transformer Approved Drawings, (arrangements, schematics, wiring, single line)
Power Transformer Weld Procedures and Procedure Qualification Records (if applicable)
Power Transformer Material Test Reports
Power Transformer Calibration Certificates for Test Equipment
Power Transformer Special Procedures
Power Transformer Special Qualifications
Power Transformer Preparation and Painting/finishing Procedure
Power Transformer Packing List
The inspection is done based on approved drawings.
Material Inspection
The third party inspector examines the original or authenticated copies of mill certificates of material for compliance with specifications, and where appropriate, drawings.
The review includes checks on:
Maker’s name and location
Certificate number, grade
Batch number
Chemical composition
Mechanical Properties
Cast number
Heat treatment condition
Surface finish
Structural observations, notable defects
Instruments normally are supported by instrument calibration records.
Then the inspector witnesses the materials identification on the certificates against the materials marking. It is also necessary to check these with the power transformers drawing datasheet, material list and other specifications as appropriate. Visual inspection for surface finish and probable defects is done and dimensional compliance with specification need to be controlled, as well.
The third party inspector carries out the material inspection and provides the inspection visit report (IVR), containing the following items:
Confirmation of satisfactory document review
Record of the endorsement of certification reviewed/witnessed
Record of all non-conformities
Record of any tests witnessed and the result
Third Party Inspection for Power Transformer – Fabrication
After material inspection was carried out, and the non-conformities were closed by remedial action, then the manufacturer starts fabrication/ welding.
The third party inspector checks the following points on the power transformers, based on the inspection and test plan (ITP).
Fabrication, protective finishes and cleanliness of all tank areas and of formers and frames
Correctness of windings, terminations, insulation, spacing and general construction
Freedom from damage (with particular attention to insulation), contamination and foreign objects
Manually check security of wedges
Third Party Inspection for Power Transformer - Construction Check
The third party inspector checks following in accordance of approved drawings and applicable standards:
Paint using specified colour swatch, measure thickness, if specified
Name plate
Outline dimensions, interface dimensions and clearances and other specified dimensions
Third Party Inspection for Power Transformer - General Arrangement Check
The third party inspector checks that all instruments, terminal boxes, compartments, control switches etc. are correctly rated and are correctly located, with specified labelling
Third Party Inspection for Power Transformer - Winding Resistance Test
Resistance of all windings are measured, with winding temperature at recorded ambient, using a milliohmeter and acceptance criteria is power transformer datasheet.
Third Party Inspection for Power Transformer - Winding Ratios Test
Primary to secondary winding ratios, for each phase, for all tappings are measured using a ratiometer and acceptance criteria is power transformer datasheet.
Importance of Using High Test Voltage for Transformer Turns Ratio Test
July 13, 2021
https://www.dv-power.com/transformer-turns-ratio-high-test-voltage/
Third Party Inspection for Power Transformer - Temperature Rise Test -Type Test
https://www.electrical4u.com/transformer-oil-and-winding-temperature-rise-test/
https://vietnamtransformer.com/our-news/temperature-rise-test-of-oil-immersed-transformer
Third Party Inspection for Power Transformer - Load Loss Test (Copper Loss)-Type Test
Third Party Inspection for Power Transformer - No Load Loss Test (Iron Loss)-Type Test
Third Party Inspection for Power Transformer Efficiency –Type Test
Efficiency is calculated from the losses.
Third party inspector reviews the calculation in manufacture quality control records.
Third Party Inspection for Power Transformer - Induced Overvoltage Withstand Test (Overpotential Test)
There are three methods; dependent on winding category, the test would be acceptable if no collapse occurs in test voltage.
Third Party Inspection for Power Transformer - Dielectric Test
Test requirements vary with winding category and acceptable level is in according to applicable standard.
Third Party Inspection for Power Transformer Separate Source Voltage Withstand Test
Third Party Inspection for Power Transformer - Ancillaries Test
Ancillaries normally include “Buchholz” oil pressure protection, temperature monitoring devises and ancillary wiring. These are checked as conforming to drawings. Wiring is subjected to insulation test, where appropriate and withstand test, where appropriate.
Third Party Inspection for Power Transformer - Reporting
The third party inspector provides an Inspection Visit Report (IVR) after each visit, as well as a final report summarizing the activities carried out during the power transformer production in accordance with the contract requirements and circulated within the time limits specified in the contract.
The report is in the format required by the client and clearly indicates final acceptance or rejection of the power transformer.
Third Party Inspection for Power Transformer - Release Note
When required by the contract or purchase order, a release note is issued by the third party inspection agency and given to the manufacturer when the power transformers have been accepted.
Third Party Inspection for Power Transformer - Packing, Marking and Shipping
The following points are checked by the third party inspector for packing and shipment inspection:
Verify that the packing materials conform to specifications and accepted practice for the mode of transport.
Verify protection against humidity, abrasion, distortion and other damage
Verify shipping marks to marking instructions and record.
Verify handling marks.
How are transformers tested? Explore testing methods and measurement tips!
https://www.hioki.com/global/learning/common-devices/transformer-test.html
Subject in Electrical Engineering: Testing and Commissioning of Electrical Equipments (2180901)
Testing of Transformer, Plant and Equipment
General Requirements for Type, Routine and Special Tests, Measurement of winding resistance; Measurement of voltage ratio and check of voltage vector relationship; Measurement of impedance voltage/short-circuit impedance and load loss; Measurement of no-load loss and current; Measurement of insulation resistance; Dielectric tests; Temperature-rise, insulation and HV test, dielectric absorption, switching impulse test. testing of Current Transformer and Voltage Transformer, power transformer, distribution transformer, CVT and special transformer with reference to Indian Standard (IS). Drying out procedure for transformer. PI index, Commissioning steps for transformer, Troubleshooting & Maintenance of transformer. [Ref: IS 2026:Part_1-10-Power Transformers: Methods of Test; IS 13956:1994-Testing Transformers]
Reference Books
Sr. Title Author Publication Amazon Link
1 Testing and Commissioning of Electrical Equipments S. S. Rao Khanna Publishers Delhi
2 Electrical power equipment maintenance and testing Paul Gill CRC Press
3 Installation, commissioning and maintenance of Electrical equipment Singh Tarlok S.K. Kataria and Sons
4 Electrical Equipment Handbook: Troubleshooting and Maintenance
Industrial Engineering of Transformer Related Activities
"Implementation of Six Sigma Program for Lean Manufacturing “To reduce the rework waste in Transformer manufacturing unit by eliminating defect of leakage from bushings in oil filled transformers”,"
Bhanpurkar, Anand; Bangar, Ajay; Goyal, Sanchay; and Agrawal, Pavan (2012) "Implementation of Six Sigma Program for Lean Manufacturing “To reduce the rework waste in Transformer manufacturing unit by eliminating defect of leakage from bushings in oil filled transformers”," International Journal of Mechanical and Industrial Engineering: Vol. 1: Iss. 3, Article 9.
DOI: 10.47893/IJMIE.2012.1039
Available at: https://www.interscience.in/ijmie/vol1/iss3/9
DOI:10.47893/IJMIE.2012.1039
https://www.interscience.in/ijmie/vol1/iss3/9/
https://ssrc.mit.edu/programs/seari-systems-engineering-advancement-research-initiative/project-transformer-4-0-digital-revolution-of-power-transformers/
Dissolved Gas Analysis Equipment for Online Monitoring of Transformer Oil: A Review
Sensors (Basel). 2019 Sep 20;19(19):4057. doi: 10.3390/s19194057.
https://pubmed.ncbi.nlm.nih.gov/31546981/
The 750kV Transformer Condition Assessment Based on Improved Grey-Target
Authors
Xi He, Ruiping Zhang, Haiying Dong
Available Online November 2016.
DOI https://doi.org/10.2991/aiie-16.2016.116
https://www.atlantis-press.com/proceedings/aiie-16/25866418
Ud 27.9.2022, 27 Sep 2020
Pub 5.12.2020
Thanks for sharing these essential tips on electrical inspection procedures! It's like having an electrical safety coach, preparing us to conduct thorough inspections and maintain a safe and efficient electrical system at home. 🌟🔍 #SafetyCoach #ElectricalInspection
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