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:

Susan McNelly

Xcel Energy

414 Nicollet Mall, MP08

Minneapolis, MN  55401

U.S.A.

Phone: (612) 330-6904

Fax: (612) 573-9190

E-Mail: sjmcnelly@ieee.org 

C57.139 Working Group Chair:

E-Mail: david.wallach@duke-energy.com

C57.139 Working Group  Secretary:

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 

Fall 2011 WG Minutes - Unapproved  Posted 2Nov2011

Fall 2011 WG Agenda  Posted 08Oct2011

Fall 2010 WG Presentation on LTC Differences - Jim Dukarm  Posted 12Nov2010

Compiled list of Recirculation 2 Ballot comments and responses   Posted 10Oct2010

PC57.139, Draft 16 - final recirculation version  Posted 10Oct2010   Requires the use of the regular Committee username and password  

PC57.139 D13 - LTC DGA Stats Calculator   (Excel file) Posted 03Mar2010   Requires the use of the regular Committee username and password 

Spring 2009 Jim Dukarm presentation on Statistical DGA Limits for LTCs   Posted 21Apr2009

Previous Meeting Info:

LTC DGA Limits Algorithm Example   Posted 21Apr2009

Jack Harley Comments - Safety Warning   Posted 21Apr2009

Paul Griffin Comments  Posted 22Apr2009

Fall 2008 Dukarm Presentation   Posted 4Oct2008

Spring 2007 Wallach Presentation  (1.1MB) Posted 30Mar2007

Spring 2007 Xu Presentation   (387kB) Posted 30Mar2007

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

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