Project scope: 

This guide discusses and recommends methods of testing and evaluating dissolved gases in mineral based transformer oils found in Load Tap Changers (LTCs).  General types of LTC mechanisms, breathing configuration and electrical design will be included as evaluation criteria in determining when mechanical damage or failure can occur. Dissolved Gas Analysis (DGA) provides a non-invasive means of signaling when maintenance of the LTC is required.  This guide will provide the information needed to develop a baseline health curve for any type of equipment covered within and will provide basic gassing levels.  Ultimately, the user must set their own standards based on local conditions.

Insulating Fluids Subcommittee Chair:

Rick Ladroga

Doble Engineering

Marlborough Executive Park

65 Boston Post Road West

Marlborough, Massachusetts

Phone: (617) 393-3133

E-Mail: rladroga@doble.com

C57.139 Working Group Chair:

E-Mail: fjakob@weidmann-acti.com

C57.139 Working Group  Secretary/Technical Editor:

Susan McNelly

Xcel Energy

250 Marquette Avenue, Suite 800

Minneapolis, MN  55401

U.S.A.

Phone: (612) 330-6904

Fax: (612) 573-9190

E-Mail: sjmcnelly@ieee.org 

Spring 2008 WG Minutes - Unapproved:   Posted 20Mar2008

Spring 2007 Wallach Presentation:   (1.1MB) Posted 30Mar2007

Spring 2007 Xu Presentation:   (387kB) Posted 30Mar2007

C57.139, Draft 9a:  Requires the use of the regular Committee username and password

GE DGA data for LTC's:  ,   Manufacturer Code Index:    Posted 8Mar2006, These two files are accessible by WG Members only by means of a special username and password.

Weidmann-ACTI DGA data for LTC's:  Posted 8Mar2006, This file is accessible by WG Members only by means of a special username and password.

Proposed LTC Type Table for discussion at Fall 2005, Memphis Meeting:

A Nomograph for Interpretation of LTC-DGA Data, presented at NETA Conference, San Antonio, March 15, 2004 by Fredi Jakob, Karl Jakob, & Simon Jones of Weidmann-ACTI and Rick Youngblood of Cinergy: