Latest News

2010 NDT Training Course Schedule is available now!

WINS acquires state-of-the-art equipment for enhanced Guided Wave Inspection Services for Pipelines and Bridge Cables, November 2009.

WINS delivers Acoustic Emission Level III Training Course in Kuala Lumpur, Malaysia, October 5-9, 2009

WINS is awarded contract with U.S. Department of Energy for developing inspection technology for health monitoring of coal power plant components, August 2009

WINS presents a paper at NYC Bridge Conference titled "Structural health monitoring using wireless acoustic emission sensor network" in August, 2009

WINS is awarded contract with NSF for developing inspection technology for Steel Piles, July 2009

WINS presents  "Acoustic emission input to inspection-based bridge maintenance" at the International Conference on Fracture & Fatigue in July, 2009

WINS is awarded Market Access Grant from Pennsylvania IBD to launch Joint Venture in India, May 2009

Transformer Inspection using Acoustic Emission

Acoustic emission (AE) is a nondestructive testing technology that may be used to detect and locate partial discharges (PD) in oil-immersed power transformers and reactors.   The technology may be applied to factory and field transformers.  AE testing is commonly used after PD has been detected by another diagnostic procedure such as dissolved gas analysis or electrical measurement.

AE testing may be used to detect and locate PD from:

  • The outside of the winding

  • Between the core and the tank,

  • Arcing/tracking of the oil surface

  • Arcing/tracking of the bushing surface in the oil

  • The de-energized tap changer

  • The on-load tap changer.

PD detection from within the winding, and in between the winding and core, is difficult due to acoustic emission attenuation.

WINS uses the guidelines set forth in IEEE Standard C57.127-2007  "Guide for the Detection and Location of Acoustic Emissions from Partial Discharges in Oil-Immersed Power Transformers and Reactors for all inspections".

Partial discharges in oil-immersed transformers emit acoustic energy that may be detected using sensors mounted on the tanks outside wall. Acoustic emission from partial discharges are analyzed according to their intensity or amplitude, rise time and counts.    Intense partial discharges from the outside of the winding, for instance, emit high amplitude PDs.  PDs from within the winding are generally low amplitude and difficult to detect.

Other parameters including load current, pump current, temperature, and load tap changer motor current may be acquired and  correlated with AE data to identify the operating conditions that cause PD.