High PD activity ...
... lead to uncovering a critical problem - the incorrectly installed wedges
Company: Midwest US Utility
Ratings: 173 MW, 18 kV, Hydrogen Cooled Turbine Generator, 3 years in operation
Manufacturer: Confidential
Related Info: 25 years old
PD Sensors: Two bus couplers per phase
Case Study Details:"... With the high H2 pressure (30-35 psig) the [PD] levels were expected to be very low but instead were very high after only a year of operation. We initially expected to find problems with the couplers as we did not believe the results..."
High PD activity (slot discharge)...
...was a foresign of an upcoming failure
Company: Western Canadian Utility
Ratings: 184 MVA, 13.8 kV, Air Cooled Hydro Generator
Manufacturer: Confidential
Related Info: 25 years old
PD Sensors: Four PDA Couplers per phase
Case Study Details: The PD data for this unit has been trended for over ten years. In 1995, semi-conducting paint and CRTV were injected into selected bars ...
Intelligent on-line signature analysis...
...revealed broken rotor bars
Company: A large utility in the US northeast
Ratings: 3000hp, 6.6kV 1785rpm Motor
Manufacturer: Confidential
Case Study Details: The suspicion arose from a constant hum during motor operation and abnormal vibration levels during start-up and running. The plant vibration monitoring system did not have the ability to zoom...
High level system PD noise...
...uncovered a well-developed tracking
Company: Italian utility
Ratings: 390 MW, 20kV, Hydrogen Cooled Turbine Generator
Manufacturer: Confidential
Related Info: Installed in 1970
PD Sensors: Two Bus Couplers per phase
Case Study Details: During a partial discharge measurement using the TGA-B portable instrument, high levels of PD activity (over 3000mV position, well above the highest range, see Figure 1) were detected on the C phase outside...
Reading Instability...
...uncovered internal bad connection on a new transformer
Company: US North-West utility
Ratings: 45 MVA power transformer
Manufacturer: Confidential
A customer was commissioning a new 45 MVA power transformer delivered by an overseas manufacturer. During the test, ADWEL's Digital Winding Resistance ReporteR, DWR-10, was consistently issuing a warning of current interruptions, and did not complete the test. Another DWR-10 instrument was used with similar outcome. All other standard measurements, including TTR, Tan-Delta and insulation resistance indicated acceptable resistance value.
Nevertheless, the customer drained the oil and inspected the transformer to detect that the windings on all 3 phases were not properly secured to the bushings. Had the transformer been energized, a catastrophic failure could have occurred.
3110 American Drive
Mississauga, Ontario
L4V 1T2 CANADA
Telephone: +1-905-677-4824
Fax: +1-905-677-8498
Sales: sales@irispower.com
Technical Support: techsupport@irispower.com
10101 Southwest Freeway
Suite 400, Houston, TX 77074
Telephone: +1-281-207-5322
Fax: +1-281-207-5323
Email: croache@irispower.com
Location: Click to view map
Acorn House
Greenhill Crescent
Watford WD18 8AH, UK
Telephone: +44 (0) 1923-254433
Fax: +44 (0) 1923-218278
Email: info@irispower.co.uk
Location: Click to view map
KCTG India Pvt. Ltd.
IRIS Power Division
10th Floor, Corporate Park-II, Sion-Trombay Road,
Chembur, Mumbai-400071.
Telephone: +91 22 67717171 Fax: +91 22 67717161
Cell: +91 9833685192
Email: ksraj@irispower.com
Room 1007, Century Trading Building A,
No. 72, Xisanhuan North Road,
Haidian District,
Beijing 100037, China
Telephone: +86-10-5179-8912
Fax: +86-10-5179-8920
E-mail: rwu@irispower.com
©Copyright IRIS POWER 2008 All Rights Reserved Privacy Statement
