The Optimus is designed to reduce the possibility of unplanned outages and help prevent catastrophic transformer failures.
Image Credit: Vaisala
A transformer’s lifetime is determined by the condition of its solid insulation, which can be detrimentally affected by air leaks. The easiest and most robust way to reliably detect such leaks is to continuously measure the Total Gas Pressure (TGP) of all dissolved gases in the transformer’s oil, where oxygen and nitrogen are the dominating components. TGP therefore provides real-time detection – even in the very early phases - of air leaks into a sealed power transformer’s tank. With the benefit of TGP, decision- makers in transformer maintenance learn whether the insulation system of a sealed transformer is exposed to air, which allows them to make informed decisions on actions such as oil degassing or sealing system repair.
The real-time monitoring of fault gases by dissolved gas analysis (DGA) is a well-known and established method for the early detection of quickly evolving faults. However, some processes develop slowly in transformers – oxidation for example, can affect their operational life, usually taking years to show significant effects. Vaisala has therefore developed its DGA monitors to track the key parameters and thereby automate effective transformer condition assessment.
Why Measure Oxygen?
In the past, oxygen measurement failed to detect slow air leaks when active oxidation processes were simultaneously consuming oxygen. However, slow air ingress can be easily detected with increasing TGP because nitrogen, as an inert gas, would not be consumed nor produced in the transformer. The latest version of the OPT100 is therefore able to combine the TGP value with oxygen measurement to determine whether oxygen consumption due to active oxidation is taking place.
With the benefit of TGP and oxygen monitoring data, it becomes possible to weigh the expected lifespan of the transformer against the costs of investigating and repairing the air leak or implementing mitigation measures. Therefore, traditional DGA of fault gases enhanced with TGP and oxygen measurement represents the ideal monitoring concept for the reliable protection of transformers.