Online Dissolved Gas Analysis
Transformer and Load Tap Changer (LTC) assets are among the most expensive pieces of equipment for electric utilities. Preserve these assets by using an appropriate DGA (Dissolved Gas Analysis) diagnostic method to improve service reliability, avoid transformer failure, and defer capital expenditures for new transformer assets.
Monitoring and assessing transformer and LTC health (especially with aging and overloaded equipment) is essential for maintaining optimal operation and avoiding downtime. All transformers experience electrical and thermal stress on the insulating materials over time. As the stresses increase, the insulating oils breakdown and can result in transformer faults.
Monitoring the dissolved gas levels in transformer oil samples is a useful, trusted maintenance tool for assuring optimal asset health. However, conventional manual methods are periodic and expensive, while real-time monitoring solutions are more proactive and lower cost in the long-term.
Transformer insulating oils are made up of different types of hydrocarbon molecules. During decomposition (breakdown), there are chemical reactions between these molecules, which result in various gas formations. The gases released into the oil include Acetylene (C2H2), Ethylene (C2H4), Carbon Monoxide (CO), Hydrogen (H2), Carbon Dioxide (CO2), Methane (CH4), Ethane (C2H6), Oxygen (O2), Nitrogen (N2), and Moisture (RS). Monitoring and testing transformer oil allows operators to calculate the gas density or concentration and identify faults.
To measure the concentrations of these key gases, an oil sample from the transformer is needed. Many utilities currently obtain manual oil samples that are sent to labs for analysis and conducted on quarterly or yearly intervals. While this provides an accurate historic assessment of the transformer or LTC, it does not accurately capture the day-to-day health. In order to measure asset health on a daily basis, utilities need an online 24 hour, 7 day-a-week solution for monitoring and assessing the gas samples.
Our Solution for Online Dissolved Gas Analysis
As experienced leaders in both NDIR and Photoacoustic Spectroscopy (PAS) technology through our Andros and Innova brands, we chose industry-proven Non-Dispersive Infrared (NDIR) for our online SmartDGA® solution. NDIR is more robust and economical than PAS while providing sufficient sensitivity for DGA.
The NDIR based SmartDGA® instrument works in cycles to obtain a sample of oil, detect concentrations (in PPM) of key gases, and record the values, making them available for review in the SmartDGA Viewer software or other optional communications.
Industry recommended diagnostic tools such Duval’s Triangle, Key Gases, Rogers Ratio, and CO/CO2 ratios along with trend data are available in the SmartDGA Viewer software to help diagnose and determine the pending and occurring faults and when to take action. Operators can set up alerts when gases reach certain thresholds, allowing for true condition-based maintenance (CBM).
With the lowest Total Cost of Ownership (TCO) in the industry, SmartDGA® makes DGA available online 24 hours a day, 7 days a week to help utilities lower costs while improving safety, reliability, and efficiency. Installation can be completed in as few as 4 hours and our ultra-low maintenance solution does not require consumables, carrier gas, or scheduled calibrations.
Each SmartDGA® package includes the instrument, mounting hardware, connection cable, the SmartDGA EZHub™ unit (for power and communications), and SmartDGA Viewer Software (for reviewing collected data). With continuous DGA values, this solution develops a comprehensive analysis of potential fault conditions through monitoring of key gas levels, rates, and ratios.
At a Glance
- Less expensive, sometimes even half the cost, of other monitors
- Ultra-low maintenance
- No consumables, carrier gas, or scheduled calibrations
- Easy to install and maintain
- Versatile transformer mounting configurations, including optional inline mounting for LTC
- Cost-effective and accurate gas detection solution
- Online, continuous monitoring
- Identify faults prior to failures
- Reduce number and frequency of LTC maintenance cycles
Key Products for this Application