Transformer services

Transformer services from Siemens Gas and Power

The financial impact following the outage of a 760MVA GSU transformer can be up to

0 dollars
  • daily of lost profits.

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Transformer services

Transforming service into reliability

Whether power transformers, reactors, transformers for industrial applications, phase-shifting transformers, or HVDC transformers, transformers are crucial for ensuring a trouble-free supply of power with no interruptions. As reliable, rugged key components, they are frequently in use for decades at a time and are, therefore, subject to the unavoidable effects of aging and wear.

Strategically increase value with TLM

How can you plan your expenditures in a targeted way and systematically control the timing of new investments? How can you avoid unforeseeable outages and minimize planned downtimes? And how can you reduce the impact on the environment while maximizing transformer availability? The answer to all of these questions is Transformer Lifecycle Management™ (TLM™) the service concept from Siemens for all the transformers in your network, regardless of age, manufacturer, or power. We service all generations of transformers.


Our TLM service concept is designed to prevent unplanned downtimes and optimize planned maintenance measures. We are aware that you have fewer and increasingly shorter windows of opportunity even for planned service interruptions. Our response is technologies and methods that are as mobile as our experts. From oil-drying systems to high-voltage testing stations, we provide mobile repair workshops to support you on-site. Mobile teams and technologies are elements that ideally complement the performance spectrum of Siemens’ repair facility. They are fast and flexible and can be integrated in your operations.


Highlight services for transformers

Transformers are the cornerstone of power generation, transmission, and distribution systems. Their outages or failures usually have far-reaching consequences on large parts of the power system.

We will get your transformers back in top form and without service interruptions.

The Siemens TLM™ method for extending service life minimizes the unavoidable, undetectable, and ongoing aging process that is taking place inside your transformers. Our stationary and continuous transformer drying system and moisture monitoring SITRAM® DRY as well as our mobile container-mounted solution SITRAM REG for the lasting regeneration of the transformer oil filling are internationally-recognized technologies, and round out our offerings for improving cooling efficiency sealing. These can easily be integrated as retrofit solutions. The regeneration of the oil filling in particular not only eliminates frequent oil changes, but also offers substantial economic and ecological advantages, as it is performed during normal operations.

Intelligent condition diagnostics for transformers

How is your fleet of transformers really doing? Siemens TLM diagnostics makes it possible to detect the current condition with high precision and therefore classify operational reliability for all makes and models and all voltage and power levels. Especially after extraordinary events such as thunderstorms and lightning, relocations, and similar occurrences, comprehensive testing including on-site high-voltage tests is recommended – and with TLM, this is possible with the high quality equivalent to testing in the factory. Mobile TLM high-voltage tests are also used for acceptance testing following on-site repairs.


Our modular diagnostics program for power transformers SITRAM DIAG consists of three levels of analysis and many additional stand-alone modules for the selection and examination of irregular transformers in ever greater detail. You can choose the level of diagnostics that best fits your needs: Essential Diagnostics is performed during your normal operations, while the Advanced Level requires minimum outages. The ultimate level integrates high-voltage testing to optimally evaluate the operational condition and residual life span of each of your power transformers, based on our decades of experiences and highly advanced diagnostic methods. 

Transforming knowledge into availability

Service overview

Services for your transformers throughout their entire lifecycle

Siemens TLM is based on the expertise available in all Siemens transformer factories, which are well-known for high quality and low failure rates. Our highly experienced transformer experts provide the most effective lifecycle solutions for power transformers of any age and any brand along the value chain from reactive to proactive services.
Test laboratory

Top class laboratory diagnostics for transformer materials

Do you know the chemical age of your transformer? Well we do! There are numerous complementary methods for diagnosing the transformer ageing process early and reliably. The Siemens Test Laboratory for Transformer Materials is completely focused on the laboratory diagnostics of oil-filled electrical equipment. The highly qualified personnel are constantly developing new methods for ageing diagnostics and are using this knowledge for the benefit of our customers.

100 years of know-how ensuring a long transformer life span

Siemens can look back at over 100 years of experience in the production and operation of transformers. During all these years we have developed numerous methods and parameters so that ageing processes can be diagnosed early and reliably. The life span of a transformer largely depends on the ageing of the solid and liquid organic insulating materials. In normal operating conditions, below the maximum permissible load, and with regular maintenance and care, a transformer's lifespan can be extended to well over 30 years.


Whether it is a case of new construction, operation, retrofit or repair, it is always a matter of reliably recognizing material degradation and rectifying it. For this purpose an extensive knowledge of the materials as well as a specific, precise analysis is fundamental. In order to avoid costly breakdowns, minimize downtimes and extend the lifespan of a transformer, the performance of a regular trend analysis and targeted maintenance are indispensable.

Bullet resistant retrofit

Bullet resistant power transformer retrofit

Mitigate risks and protect assets without compromising performance and reliability.

Why bullet resistant?


Power transformers are essential in the effective and reliable transmission and distribution of electricity. Serving as critical nodes, transformers have been engineered over decades to withstand operational risks such as lightning strikes, severe weather events, seismic activity and power fluctuations. However, up until now transformers have still been vulnerable to human impacts, especially those carried out with high-powered ballistics. Siemens has taken significant steps to develop and test new materials and designs that enable our transformers and reactors to withstand ballistic attacks, ensuring their physical security.


Alarming attack on U.S. power station


On April 16, 2013, an electric substation in Metcalf, California, was attacked by snipers with at least one highpowered rifle. The assailants surgically knocked out 17 giant transformers within 20 minutes. The attack resulted in an estimated $16 million in damages and a substation rendered inoperative for 27 days. Although the most well publicized, the Metcalf attack was not an isolated incident. Due to significant capital expenditure requirements and extended lead-times, best practice to ensure the reliable operation of critical transformers and reactors is to protect them from malicious attacks.

Bushing replacements

Bushing replacements for power transformers

Keeping all components of a power transformer in good operating condition is key to maintaining and extending its life.

Power transformer bushings are critical components in electrical power systems as they allow for the flow of electrical power from the power stations and renewable energy sources through the transformers to the distribution networks and to customers. As vital components, it is recommended that transformer bushings be monitored, inspected and tested on a regular basis as bushing failures can result in expensive transformer failures.


Several investigations of transformer failures have been done in the past, e.g. by CIGRE Transformer Reliability Survey reference WG A2.37 dated April 2012. According to these investigations bushing failures caused 17% of transformer failures. Unplanned power outages due to transformer failures may affect the reliability and availability of your system and ultimately your customers and revenue, especially if you do not have a spare transformer readily available.

Downloads, support, and services

One step ahead with information

Get to know more about our services for your transformers. We will gladly place our information material on our transformer services, training courses, newsletters, and more at your service.

Mailing address

Siemens Industry, Inc.

7000 Siemens Road

Wendell, North Carolina 27591

United States

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We are at your service.

If you would like to learn more about what we can do to keep your transformers fit for tomorrow’s energy demands and technological, economical, and safety-related requirements, please contact us. Our experts look forward to answering all your questions about our transformer services, and we will be pleased to provide you with comprehensive information.

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