by Nova Energy Consulting Pty Ltd

Interpret Dissolved Gas Analysis like a pro

The challenge of managing Power Transformers

A critical aspect of managing assets is to understand their condition, their

performance against the organisation's objectives and the level of risk they


Power transformers and other insulating liquid-filled assets are critical

component of electrical grids. These are typically very expensive assets with

long replacement lead times.

Utilities and other asset intensive organisations depend on assessments

performed by Subject Matter Experts (SME) to make the most effective and

efficient decisions. These SMEs are also busy dealing with all sort of

emergencies and requirements from the day-to-day operation of the business.

Based on many years of accumulated experience, international reliability

surveys and the hard work of many of these SMEs around the world, the industry

has developed a range of diagnosis techniques that assist in the management of

these assets.

One of the most common techniques to assess the condition of Power

Transformers is through regular insulating liquid sampling and analysis. The

Dissolved Gas Analysis component of this suite of tests is one of the most

useful techniques to understand the transformer's condition.

This knowledge has been captured in the form of technical papers, guidelines

and various study reports. These documents are rich with information and

knowledge about the best way to assess the condition of each asset.

This documents have to be translated into an actionable algorithm or

calculation in order to be useful. Without a standard implementation, most

teams develop their own tools and calculation spreadsheets.

The use of digital tools to assist condition assessment

Digital tools can provide these SMEs the information they need to make

opportune decisions and provide sensible recommendations.

When these decisions are recorded on digital platforms, the rest of the

organisation benefits from having a consistent approach to making these

decisions. Whether they are being made by a veteran in the industry or a young

engineer or technician at the early stage of their careers.

A well-designed digital tool has the potential of supercharging the skills and

experience of asset managers.

If you’ve ever tried to apply any of the available analysis guidelines, you’ll

know that some of them are dozens of pages worth of information. Wouldn’t it

be nice if all those rules were condensed in easy-to-use formulas that can be

applied to your existing DGA data?

If only there was a tool that summarises all this knowledge and helps SMEs

apply these algorithms easily and consistently.

xDGA was created with this purpose in mind.

What is xDGA?

xDGA is an Excel add-in tool that implements a set of custom

formulas. These formulas enable is users to run industry best-practice

algorithms to evaluate and assess the results of Dissolved Gas Analysis in

Liquid Filled Electrical Apparatuses such as Power Transformers, On-Load Tap

Changers, Circuit Breakers, etc.

The custom formulas are packaged as an Excel add-in which doesn’t require any

additional software installed on your computer. Simply install xDGA from one

of the available sources and you'll be up and running in no time. Read our

installation guide

The main components of xDGA are as follows.

Custom formulas

These custom formulas allow you to:

  • Normalise the information required for further analysis using a DGA

    formatting function.

  • Perform automatic conversions of the "triangular" and "pentagonal"

    coordinates of the Duval chart into cartesian X,Y coordinates. This is

    useful if you want to create Duval charts in your workbook.

  • Run individual rules and diagnosis techniques such as Rogers Ratios, Duval

    Triangles, Duval Pentagons and sections of the IEC 60599 interpretation


  • Run a full assessment as per the IEC 60599 guidelines and get a "NORMAL",

    "ALERT" or "ALARM" assessment.

Read more about this feature in the Formulas section of the documentation.

Duval triangles and pentagons charts

xDGA also has the functionality of inserting any of the Duval

Triangles and Pentagons as Excel charts.

Each chart has been carefully crafted and formatted to be easily extensible by

the user. Each zone is clearly labelled and all source coordinates to draw

these areas are stored in a separate worksheet.

These charts can be inserted in seconds and will enhance any existing or new

condition report.

Read more about this feature in the Charts section of the documentation.

DGA database and report templates

Building on all these features, xDGA provides you with two starter templates.

One inserts a new worksheet that contains an Excel table DGA database that is

preformatted to act as a database for all your reporting needs.

The second is a template for a full analysis report for an individual

transformer. This report relies on the DGA database and it contains all the

necessary formulas and formatting to just select a transformer from the

drop-down list.

Read more about this feature in the Reports section of the documentation.


What are you waiting for? The add-in can be downloaded from any of the

Microsoft sources (see Installation) and you'll be up and running in a couple

of minutes.

With one free month to try out all of its features, there is no risk to you or

your team. If you don't like it, you don't buy it.

We hope you enjoy it and we welcome any feedback you might have.

App capabilities

When this app is used, it
  • Can read and make changes to your document
  • Can send data over the Internet

At a glance