Due to the unchanging design fundamentals of transformers, these asset often remain viable parts of a network for many decades. When looked after correctly, many transformers can outlive most people.
Also like people, transformers need regular health checks, monitoring of their vitals, a healthy diet and occasional intervention. If such a regime is followed, we see fewer health issues and assets that live a longer life. One of the most important vitals to monitor in a transformer is the insulation.
The Healthy Triangle: safeguarding insulation life
The insulation system within a transformer is one of the parts most prone to premature ageing is not treated correctly. There are three main factors that impact the condition of the cellulose insulation.
Moisture has a serious role in premature ageing of insulation and the performance of the dielectric fluid:
- Reduces dielectric and tensile strength of the insulation
- It increases the risk of bubbling in the insulation
- It increases the risk of partial discharge
- An increase of moisture from 2% to 3% can decrease asset life by 10 years.
A closer look at the impact temperature has on a transformer yields deeper implications than just direct loss of life.
- Overloading beyond rated design results in increased temp and accelerated ageing.
- Accelerated ageing affects both tensile and dielectric strength of the insulation.
- An increase of 20°C operating temp equals about 90% reduction in asset life.
- Network planning and asset replacement forecasts are greatly affected by undetected, premature ageing.
Acids & Impurities
A transformer is a closed system. Impurities and acids are formed from chemical reaction between system components reacting together.
This process depends upon the types of materials used and the operating temperature of the transformer. Some materials react less and produce fewer harmful impurities.
Mid-life processing of the transformer fluid can also reverse or slow this process somewhat.
Keeping your transformer healthy
We take a closer look at each of these factors, the impacts they can have, and how they can be managed. Read more in our Transformer Optimisation white paper.