Transformers are critical assets, and any failure can have severe and long-lasting consequences. In the most extreme cases, a transformer failure caused by a lack of proper maintenance can result in widespread outages, costly repairs, and regulatory fines.
Utilities need to monitor the health and performance of transformers to mitigate the risk of failure and ensure the reliability of the power grid. However, many are limited in their ability to detect and diagnose faults before they lead to failure. Periodic inspections, sampling, and scheduled maintenance, though necessary, leave the utility exposed to issues that can go undetected for weeks or months at a time in between those activities.
Visual & thermal monitoring solutions provide utilities with a continuous, 24/7 view of high-value assets and critical infrastructure.
When combined with Dissolved Gas Analysis (DGA), visual & thermal sensors allow utilities to reduce operations & maintenance costs, improve equipment reliability, and transition to a Condition-Based Maintenance strategy.
Transformer Monitoring and Dissolved Gas Analysis
A transformer monitoring system (TMS) continuously tracks the operational condition, performance, and overall health of power transformers in substations. An effective TMS monitors a variety of parameters and indicators that reflect the transformer’s health over time through a combination of in-person inspections and remote sensors. An effective TMS uses a variety of sensors and analyses to monitor the transformer and its subsystems and provides a reflection of the transformer’s overall health.
Among these, DGA is one of the most important diagnostic tools used in transformer monitoring.
DGA analyzes the gasses dissolved in the insulating oil of transformers. The presence and ratio of gasses dissolved in the oil provide an early indication of a fault, allowing operators to take corrective action and conduct a more detailed inspection.
Single gas monitoring, or key gas monitoring, focuses on detecting the presence of hydrogen gas. This cost-effective approach serves as an early warning system, while the rate of change can indicate the potential severity of the issue. However, the presence of dissolved hydrogen gas alone is not enough to definitively determine the cause without further investigation.
Multi-gas monitoring, on the other hand, measures the levels of numerous gasses, including methane, ethylene, acetylene, and others. The profile of these measurements allows for an initial assessment and identification of the incipient fault, providing a more complete diagnostics tool before crews arrive on site.
Traditionally, DGA has relied on oil samples collected from the transformer on a scheduled basis. While these samples make it possible to detect a fault at the time of the inspection, they are unable to detect issues that occur between samples, leaving the utility vulnerable to an avoidable failure in the future.
The best approach to DGA depends on the available budget and the level of monitoring required for each transformer or substation.
How Visual & Thermal Monitoring Solutions Complement Dissolved Gas Analysis.
DGA provides a detailed look at the condition of the transformer from the inside. It is effective at detecting electrical failures or issues that produce hydrogen or other gasses.
Visual & thermal monitoring solutions complement DGA by monitoring the transformer from the outside. Utilities gain continuous thermal data of critical transformer subsystems such as bushings, arrestors, load tap changers, cooling system, and connection points.
Thermal sensors monitor for sudden or prolonged temperature differentials that could indicate a potential fault.
Automated alerts notify the Operations & Maintenance department if an alarm threshold is exceeded. Operators can then view high-resolution video feeds to visually inspect assets, check gauges, and assess the conditions remotely, giving crews a better understanding of the issue before they arrive on-site.
Together with DGA, the two solutions work together to provide utilities with a complete view of the entire transformer.
Using the IM500 Industrial IoT Module With Dissolved Gas Analysis Sensors
The IM500 Industrial IoT Module is a compact, cost-effective, and easy-to-deploy visual & thermal monitoring solution designed specifically for the electric utility industry.
The sensor provides continuous thermal snapshots of critical equipment and components, enabling remote monitoring and providing greater visibility into the health and performance of their assets.
The sensor seamlessly integrates with SCADA, GIS, and other Asset Management applications so that utilities can view visual, thermal, DGA, and other sensor data in a single dashboard.
The embedded cell modem connects directly to the IoT cloud to transmit the thermal and visual data, further reducing the cost and time to deployment. In cases where cellular coverage is limited, or if the utility prefers to use an internal network, the IM500 provides Wi-Fi or Power-over-Ethernet options to connect to the SWI cloud.
The IM500 offers utilities a viable solution for thermal monitoring that can be deployed alongside other TMS approaches, including DGA.
Enabling Condition-Based Maintenance
Transitioning to a Condition-Based Maintenance strategy will require a range of sensors and solutions to ensure that utilities have access to the right data.
By deploying visual & thermal monitoring solutions such as the IM500 alongside Dissolved Gas Analysis, utilities gain a more complete view of their equipment. Instead of being reactive, utilities can detect faults indicated by the presence of dissolved gas or thermal anomalies, allowing operators to reduce the load on the transformer and conduct a repair before a catastrophic failure occurs.