For more than 40 years Dissolved Gas Analysis (DGA) has been the go-to solution for understanding and assessing the condition of power transformers in the energy sector. In the beginning the standard method was to adopt a single gas monitoring approach, this typically involved monitoring of hydrogen levels in a transformer.
Hydrogen monitoring whilst a relatively economical monitoring solution is not without its limitations. The presence of hydrogen typically signifies the presence of a fault but provides no clarification into the nature or the severity of the fault, this will only be possible through further testing. Furthermore, the occurrence of stray gassing can heighten false alarms, leading to a sense of distrust and confidence in the results provided.
Multi-gas DGA enables the analysis of multiple gases dissolved in the insulating oil of a transformer. Adopting a multi-gas DGA approach offers a more comprehensive and sensitive method for assessing the health of power transformers
Key benefits of adopting a multi-gas solution:
Today, multi gas solutions, thanks to their sensitivity and can provide early warning signs as soon as faults begin to develop. The early indication of such faults is critical to ensure operators can take corrective action on faults in their infancy, helping to avoid unplanned outage or potentially leading to more serious catastrophic failure.
- True and accurate fault detection
In DGA no one gas alone can detect all faults in a transformer. The ability to monitor multiple gases enables the scope of faults to be widened. A primary way of doing this is by correlating the concentrations of key gases in the transformer oil.
Gases produced in the insulating oil of the transformer each have their own specific characteristics and behaviours, which when analysed together can be linked back to defined fault types. The key outcome is not only the detection of the given fault but also being able to trust that the analysis.
- Data analysis and trending capability
The adoption of a multi-gas solution provides vast amounts of valuable data, enabling thorough analysis and interpretation. Through continuous monitoring of the key gases, identifiable patterns do become apparent over time, which provide key insights into the internal behaviour and condition of a transformer. Analysis and trending of this data enables asset managers to make informed and confident decisions, helping to optimize the management of your critical assets.
- Ensures cost effective maintenance strategies
Condition-based maintenance that is backed by a multi-gas approach can provide opportunities to optimize available resource allocation but also helps to reduce maintenance expenditure. Through reliable fault detection, maintenance schedules are defined by the true condition of the assets rather than predetermined timeframes. This approach helps to avoid unnecessary maintenance or premature replacement which can result in significant cost savings for utilities.
Many transformers can and are located at remote substations with no locator operators or maintenance personnel. With a digitalized online multi-gas solution, operators can be alerted to a fault in real time. Immediate investigation can take place to understand the nature of the emerging fault and the severity. Asset managers are able to make informed decisions much sooner which enables the all-important action to resolve the fault.
With single gas, offering the additional steps adds not only time but also labour costs and increased risk of further damage occurring within the transformer.
With the world moving to a more digitalized landscape the impact of new digital tools will be critical to the success of business in the future. Digital tools will automate the correlation of key DGA data, over time and can be aligned with other key parameters to provide that more holistic overview of the asset condition. This capability is dependent on the data being available, without the important understanding provided by the multi-gas data, this functionality will never be possible.
To conclude:
Throughout its history, DGA has proven itself to be invaluable in providing critical insights into transformer health. The importance of multi gas monitoring is clear to see, from providing early fault detection, to the type of fault and the severity of the fault. With the continuous need to implement asset management strategies that are cost effective and enable Asset Managers to manage their resources. Multi-gas solutions enable Asset Managers to prolong the life and reliability of these critical assets all of which is key as we move towards the grid of the future, which is reliable, efficient and resilient.
