Online monitoring of power transformers
Do you also know these challenges?
1. your transformers must operate safely until the end of their service life.
2. but they are ageing faster due to additional grid overloads and changed load flows.
3. they are also being loaded by more and more grid transients.
Online monitoring helps you overcome the above challenges so that your power transformers can be operated safely.
Cyclical measurements to assess the condition of your power transformers are worthwhile, but they only provide snapshots. Trends can be identified only after measured values have been collected and compared over a number of years. For each of these measurements, the transformer in question must be taken out of service. That is expensive and time-consuming. In addition, some measured values only have good significance when they are recorded and evaluated during operation. This applies precisely to the following important parameters:
- Oil temperature
- Humidity content in the insulating oil
- Gases dissolved in the oil (DGA)
- Capacity and dissipation factor of bushings
If you constantly monitor important parameters of your transformer, you can operate it safely, even beyond its expected lifetime. In case of anomalies in the measurement results, you can react early and relieve the transformer. This gives you the time you need to plan its decommissioning. After further measurements, you can decide whether the transformer must now be permanently decommissioned. You can thus avoid the enormous costs of a sudden total failure.
Permanently monitoring a transformer that has reached the end of its expected service life can make sense for several reasons:
- The transformer is important for your grid, but it is not redundant. Although the N-1 safety rule applies in the German power grid, it is no longer fully implemented.
- Decentralised generating plants (e.g. photovoltaics) overload your transformer frequently.
- New cable connections and reactors for reactive power compensation can lead to changed transient loads for your transformer.
- Your transformer is thermally stressed by harmonic loads.
Compare the risks of an unplanned failure of your transformer with the expenses for its online monitoring. This way you can decide whether it makes sense to equip your transformer with an online monitoring system.
