Delta-X Research
Bringing Science to Transformer Risk Management

Power transformers are designed to pass large amounts of energy with very high efficiency, so in normal operation and in the absence of unusual stress, there should be no degradation of the oil or the paper insulation inside a transformer. However, when a fault occurs, energy is diverted into the insulation material causing the formation of certain gases dissolved in the transformer oil. By measuring and analyzing these gases through dissolved gas analysis (DGA), utilities can interpret the fault-related gas data in order to detect, assess and identify the fault.

Dissolved gas analysis interpretation is a three-step process: users must first determine whether or not a fault exists; if yes, then assess how severe the fault is; and then identify what type of fault is occurring. For decades, tools like the Duval Triangle have been very good for identifying fault types, but conventional DGA interpretation methods have been inconsistent at initial fault detection and subsequent severity assessment.

A new, patent-pending approach to DGA interpretation seeks to remedy this challenge. Reliability-based DGA (R-DGA) provides an improved method to determine whether there is evidence of an abnormal condition, and if so, to reliably assess severity. Once R-DGA indicates that a fault is present, a fault type identification method such as the Duval Triangle can be applied to identify the fault. As the creators of R-DGA, Delta-X Research has incorporated this new method into is flagship product, Transformer Oil Analyst (TOA) software. Used for managing and interpreting insulating fluid test data with a statistically valid methodology, TOA helps utilities identify at-risk power transformers earlier than does conventional DGA methods and generates fewer false alarms.

Delta-X Research was founded in 1992 as a consulting company by Dr. James (Jim) Dukarm, a mathematician with extensive experience developing industrial software, including for the electric power industry, employing artificial intelligence and other advanced techniques. Initially involved in several projects related to insulation power factor testing, Jim was asked to develop a software application for managing and interpreting DGA data for power transformers. Designed as a decision support tool for asset managers and maintainers, the original TOA handled both DGA and oil quality test data and featured a fuzzy logic expert system, user-configurable interpretive criteria, and a simple and intuitive user interface. Over time, hundreds of copies of TOA were sold worldwide. Development, sales, and support of TOA became the entire business of Delta-X Research.

Equipment Maintenance Simplified

Today, Delta-X Research is recognized as a technology leader in its field with TOA’s latest version being used by over half of large utilities in the USA. TOA4 automatically interprets insulating fluid test data and delivers accurate and timely condition assessments directly to the field and key enterprise asset management systems. With high-quality intelligence, operators are equipped with the knowledge to provide reliable service and make the necessary hard decisions when circumstances change.

TOA4 also maintains the essential equipment test and assessment history that supports compliance requirements for regulators and insurers.

For utilities that have incorporated online monitoring into their systems, Monitor Watch extends TOA4 to collect and process online DGA monitor data, providing high-quality status and diagnostic information to enterprise systems. “Using Reliability-based DGA in TOA4 to interpret online DGA monitor data, particularly data for multiple gases, reduces false alarms and enhances the detection and the severity assessment of incipient transformer faults,” explains John Brett, CEO of Delta-X Research. By automating the screening and interpretation of online DGA monitor data, Monitor Watch presents statistical and graphical summaries for high-voltage equipment experts. Using sophisticated algorithms, Monitor Watch also distills the inherent noise present in online DGA monitor data, offering a timely condition assessment of the monitors in order to avoid disruptive and costly false alarms.

Using Reliability-based DGA to interpret online DGA monitor data, particularly data for multiple gases, reduces false alarms and enhances the detection and the severity assessment of incipient transformer faults

Painting the Future with Reliability-based DGA

When Delta-X Research showed R-DGA examples to its largest utility customer, they asked to conduct an R-DGA assessment of their entire 7000-transformer fleet. The client’s engineers examined the results and reported that Delta-X Research’s R-DGA method significantly outperformed conventional DGA, both by eliminating “false alarms” where a transformer is identified as abnormal without an active problem, and by detecting a large number of cases where transformers had significant problems but had not yet exceeded the 90th percentile gas concentration limits used by conventional DGA interpretation methods. In response to this remarkable validation, the client immediately incorporated R-DGA into its transformer health surveillance process.

Working towards the successful implementation of R-DGA into its TOA4 software and Monitor Watch, Delta-X Research will continue creating ripples in the high voltage apparatus market. With a unique and sound scientific basis for interpreting test data, the company’s products will continue providing accurate and timely insights into the condition of critical assets, so the electricity system can operate safely and reliably at peak conditions and maintenance teams can be deployed most cost-effectively. “At Delta-X Research, it is very important to continue our research and apply first principles science in order to properly understand the early indications of failure in high-voltage equipment,” says Brett. “This is the rigor required so our customers can confidently manage the risks associated with operating the electricity system.” With continuous research, the company ensures its products remain innovative and support its clients as they make difficult decisions regarding the maintenance, refurbishment or replacement of their critical assets.