Prevent transformer failures and costly outages before they happen

Author: Yuri Rossini

08/14/2018

Components in energy systems everywhere are aging, even as power requirements continue to increase. The current environment of higher loading on aging transformers, deferred capital expenditures as well as increased service reliability requirements suggests that transformer owners should take advantage of the improved on-line monitoring offerings available in the market today to get the best protection for these valuable assets.

 

Customer challenge

 

Power transformers and reactors have a long life cycle and play a key function in the energy chain. Found at industrial plants and substations, these important pieces of power equipment must always operate securely and reliably to keep operations running and to avoid any immediate hazards to people, the environment and other equipment. A transformer’s operation should be continuously optimized to fit the performance required by the owner and always take life extension into consideration. With physical as well as chemical aging factors impacting reliability, it can be a challenging task to combine the two targets because transformer life extension depends on several factors, including operational demand which is dynamic. Efficient, condition-based maintenance of equipment, like transformers, is playing an increasingly important role as a means of safeguarding operation and minimizing risks – meaning that even transformers are entering the digital age.

Reasons and impacts of transformer failures

The importance of analysis

 

When condition-based data is not available and there is a lack of information to guide a transformer’s or reactor’s operation and maintenance, some conservative actions must be taken, such as offline testing and programmed outages. These actions might be satisfactory as a first line approach, but this is not the optimal way to manage these critical and costly assets. A digitalized, condition-based monitoring option can help manage equipment operation, avoiding unnecessary outages, and can also help with planning, reducing insurance policies in most cases, and significantly reducing the risk of an incipient failure. In summary, online monitoring can show the best financial return on these expensive assets, extending life and optimizing performance.

The future market trends towards a holistic online transformer condition monitoring via digitalization

Our solution to the customer challenges

Using our long-term knowledge as a transformer manufacturer, Siemens has created a system with embedded technology to evaluate the condition of transformers and reactors. The solution, SITRAM® TDCM, is capable of a complete data evaluation that supports customers with a comprehensive description of the equipment’s condition, including: detailed diagnostic of incipient failures even in the earliest stages; prognostics based on the current operation and possible scenarios derived from the condition; recommended actions for maintenance and prevention of a failure evolution; trends for first recognition of future critical conditions.

If an abnormal gas increase trend is detected by SITRAM® TDCM, the system will evaluate the current condition of all monitored variables, along with historic data, and identify the most likely reasons for the trend. The report generated will show the possible causes for the occurrence (e.g. overload, temperature increase, cooling system malfunctioning) and the necessary actions to mitigate the problem and/or avoid further development until a solution can be executed. This correlation made by SITRAM® TDCM is a key factor for an accurate evaluation as there are several reasons that can lead to a transformer failure. Surpassing any kind of alarm detection system, SITRAM® TDCM provides customers with real condition diagnostic.

SITRAM® TDCM also has the ability to provide fleet evaluation when more than one transformer is integrated. The system is capable of comparing equipment with sister units to map abnormal behaviors. Each transformer is unique in importance and characteristics, and the SITRAM® TDCM learns the operation mode from each unique unit to create a signature that differs from the other units based on possible failure conditions from any recurrent situation in which the transformer is subjected. This singular operation mode is also taken into account for the fleet-wide evaluation, increasing the accuracy of failure detection and differentiation between regular and abnormal operation.

One of the most powerful modules from SITRAM® TDCM is the Dynamic Loading Tool that calculates in real time the possible load or overload permissible for the transformer, considering its current operational data, environment conditions and historic data. With this tool the system is able to advise if an overload can develop into a failure condition, or if it will affect the transformer’s health. SITRAM® TDCM is able to simulate the transformer’s aging process based on the load condition requested, allowing the potential consequences to be evaluated prior to actually executing the desired load.

In addition, to fulfill a robust portfolio of transformer monitoring solutions, Siemens has a family of sensors to collect specific data signals from Siemens or other OEM transformers and reactors. The most recent equipment in this family is SITRAM® Multisense, a multi-gas sensor that can be found in two different options: the SITRAM® Multisense 5 which monitors 4 fault gases and moisture, and the SITRAM® Multisense 9 which monitors all 8 fault gases that may be present in transformer oil and moisture. The Multisense line has an innovative technology with accurate measurements and a stable application for field installation which makes the device a desirable solution for deep DGA analysis. The sensors can be used as stand-alone or integrated with SITRAM® TDCM.  Due to its advanced technology, the installation of SITRAM® Multisense is easy. With no moving parts to suffer interference from noise or vibration, the sensor is almost maintenance-free.