“Can we really install DGA online monitoring system to a live transformer?”
This is a question I hear often when a new customer is planning their very first OPT100 installation. Many companies still believe that every instrument installation to transformer is difficult and expensive procedure. They are worried about timing, expenses and arrangements related to de-energizing the transformer and calling in various subcontractors to the site at the right time.
Nine out of ten cases Vaisala Optimus OPT100 or MHT410 can be installed to a transformer without powering the transformer down. Most demanding tasks with OPT100 installation are usually building the pipeline and connecting the monitor to SCADA (Supervisory Control And Data Acquisition), basic things that can be commonly done by plants own maintenance personnel without external help.
Those 10% of installation cases, that require de-energizing the transformer, are usually related to safety regulations of the customer, or safety limits of the transformer. Some companies have rules that strictly forbid working around energized transformer and sometimes only available valves for incoming and returning pipelines are above the safety limits. When building pipelines to a high location above safety limits, it might be a good idea to install extra valves to lower point along the pipeline, so the oil flow to DGA unit can be controlled within the safety limits.
During the planning of the installation, or even during the actual installation, some unforeseen challenges may appear. Very old transformers might have valves with uncommon thread types that are difficult to identify, not to mention procuring correct fittings. If a fitting is not commercially available, custom adapter can be designed and manufactured at local workshop. In worst case, solving this kind of surprises can take weeks to handle. Many power plants and other industrial sites have extraordinary well-equipped workshops, which can create the adapters in a day! Even if you have a good workshop available, I would recommend planning these things well in advance.
During the OPT100 research and development phase, our team took part in various installations around the globe to gather knowledge of site-requirements and environments. The environments varied a lot from desert at Middle East with scorching sun and +45°C to North Lapland with -20°C and arctic breeze.
After experiencing the both extremes, and quite a few in between, I must say the most unpleasant installation environment is any, with heavy rain. No matter what you wear, you will always get soaked, and attempts to protect the pipes and installation laptop from excess moisture can be quite hilarious. As OPT100 has IP66 rated enclosure and the door must be opened only few times during the installation, the rain itself is not an issue for the unit, but we do not want to get any extra moisture inside the pipes during the pipe-building phase. With careful preparations and following the installation manual’s steps every installation -even in heavy rain- can be a success.
It’s always a very satisfying feeling to get the first measurement readings to the control room from the recently installed unit. Customers have been especially happy with the fact that no software installations are needed, and the measurement data and settings are available with web browser based user interface. Installation completed.