Preventive and Corrective Maintenance of the Transformer
- Grupo Edmar
- Sep 11, 2025
- 3 min read
Updated: Sep 12, 2025
September 11, 2025 - Preventive and Corrective Maintenance of the Transformer
Preventive and Corrective Maintenance of the Transformer.
Electrical transformers are the heart of any power distribution network. Their proper operation ensures that electricity reaches homes, businesses, and industries with quality and stability. However, as these devices operate 24/7 under demanding conditions, they require constant maintenance to prevent failures and prolong their useful life.
Here we will explore in detail the two main approaches to maintenance: preventive and corrective , their differences, advantages, and when it is appropriate to apply one or the other.
Why is maintenance important in transformers?
A transformer may seem like a robust and almost indestructible piece of equipment, but in reality it is exposed to multiple factors that deteriorate its performance over time:
Electrical overloads that cause overheating.
Adverse environmental conditions such as humidity, dust, salinity or extreme temperatures.
Aging of materials , such as oil or winding insulation.
Mechanical vibrations due to sudden changes in the network.
If not detected early, these factors can lead to serious failures, extended shutdowns, or even electrical accidents. Proper maintenance not only prevents costly repairs, but also ensures operational continuity and improves the transformer's energy efficiency.
What is preventive maintenance for a transformer?
Preventive maintenance is the most recommended for all types of transformers. These include periodic, scheduled inspections that aim to detect anomalies before they become serious problems.
Common actions within this type of maintenance:
Dielectric oil tests , to evaluate the quality of the insulation.
Visual inspection and cleaning of insulators, connections and bushings.
Electrical tests for insulation resistance, dielectric strength and power factor.
Review of cooling systems , such as radiators or fans.
Temperature measurement at critical points to prevent overheating.
The most valuable aspect of this scheme is that it allows shutdowns to be planned and scheduled without affecting the facility's daily operation.
What is corrective maintenance?
Corrective maintenance is applied when a failure has already occurred or the transformer has presented an anomaly that takes it out of service.
Some typical interventions include:
Repair or replacement of damaged windings.
Correction of oil leaks in joints or tanks.
Replacing Buchholz temperature switches or relays.
Changing cracked insulators or nozzles.
Drying of insulation due to moisture ingress.
This type of maintenance has the disadvantage that it cannot be planned , and generally involves high costs and downtime that can impact production or electricity supply.
Main differences between preventive and corrective maintenance.
Although both aim to extend the life of the transformer, their approaches are completely different:
Aspect | Preventive | Corrective |
Aim | Prevent failures and anticipate problems | Correct damage that has already occurred |
Planning | Scheduled and scheduled | It happens unexpectedly |
Cost | Low and controlled | High and unbudgeted |
Operational impact | Minimum, short and planned stops | Stop, long stops and risks of interruption |
Equipment lifespan | It is significantly prolonged | It can be reduced by recurrent damage |
In simple terms: preventive protects your investment and corrective reacts to emergencies .
Advantages of Preventive Maintenance.
Choosing a preventive maintenance plan provides key benefits:
Greater electrical safety , reducing the risk of fires and short circuits.
Cost optimization , since problems are detected in time and major repairs are avoided.
Greater operational reliability , the transformer remains available whenever needed.
Extended useful life , as accelerated wear is reduced.
Regulatory compliance , in many sectors regular maintenance is a legal obligation.
For example, in an automotive plant, a failure in the main transformer can halt all production, generating losses in the millions. With a preventive approach, these risks are reduced to almost a minimum.
Advantages of corrective maintenance.
Although corrective maintenance is usually more expensive, it is also important:
Allows you to resolve unexpected failures immediately.
It is used to modernize old equipment and replace obsolete components.
It may be sufficient in secondary or low-criticality equipment , where a stoppage does not represent a major loss.
For example, in a backup transformer, applying corrective maintenance can be more cost-effective than implementing constant periodic reviews.
Which one is better to use?
The smartest answer is to combine both approaches:
Preventive to ensure continuity in main or critical transformers.
Corrective as an inevitable response to unforeseen events.
However, preventive maintenance should always be the foundation of any plan, as it reduces the likelihood of major failures by up to 70%.
A clear example is the hospital sector: there, you can't rely on corrective measures, as a shutdown can put patients' lives at risk. Therefore, preventive maintenance is rigorously scheduled. At Grupo Edmar, we know that each transformer has different operating conditions, which is why we offer customized preventive and corrective maintenance plans .
Our technical team is trained to service medium- and high-voltage transformers, performing everything from routine testing to specialized workshop repairs.
With us, you not only get technical service, but also expert advice to maximize the efficiency and safety of your electrical infrastructure .
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