Details

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Essential DGA monitoring for transformers

Transformers are key and expensive components of the electrical grid and knowledge of their health condition is essential to having a reliable network. When a transformer’s insulation system is overstressed, gases are produced that dissolve in the oil. Dissolved Gas-in-oil Analysis (DGA) is recognized as the best indicator of developing faults.

The Hydran™ 201Ti is a small and easy to setup continuous Dissolved Gas-in-oil Analysis (DGA) monitor. It provides the basic information used by IEEE® Standard C57.104 and can be used as an essential first line of defence for the transformers in your fleet to obtain advance warning of a failure condition and minimize the risk of unplanned outages.

The 201Ti’s composite-gas sensor provides the world renown “Hydran gas value” using fuel cell technology (described as fixed instruments - method 3 in the standard). It responds 100% to Hydrogen (general fault gas) and is also sensitive to Carbon Monoxide (overheated paper), Acetylene (arcing) and Ethylene (overheated oil), thus covering all the main transformer failure root causes.

Because the monitoring unit mounts on a single valve and uses Dynamic Oil Sampling, there is no need for a pump or extra piping to connect to different valves. Due to its uncomplicated features and the easily understood information it provides, the 201Ti has been amongst the monitors of choice for many years, with one of the largest installed base of any monitor.

Key Benefits

• Continually measures composite fault gas to give you an insight into the transformer’s condition
• Communicates gas ppm and gas rate of change values remotely to avoid site visits and enable remote supervision
• Fourth generation of this proven and continuously improved design, with over 25,000 units sold worldwide
• Supports new lower flammability ester based oils as well as mineral transformer insulation oils

Applications

Power Utilities

• Simple and effective solution for less-critical transformers
• Focuses and prioritizes asset replacement strategy

Industrial Plants

• Reduces the risk of process interruption due to power failure
• Minimizes costly production downtime

Controllers

The Hydran 201Ti can be connected to optional controllers to facilitate communication with multiple units and create a local network.

• The Ci-1 controller is a one channel controller that replicates some of the human interface functions (gas value display, alarm buttons). This is ideal when the 201Ti is mounted out of reach on an upper valve of the transformer. It also brings down the alarm relay contacts and the analogue output for easier wiring.
• The Ci-C controller receives the gas ppm data from up to four 201Ti, providing a single communication point for all four monitors. It has no alarm relay or analogue output. This is ideal when protecting 3 single phase transformers + 1 spare.

It is possible to “daisy-chain” up to 32 controllers or 201Ti through their RS-485 port. The maximum chain distance (all cables added up) is 1200m (4000ft). All the 201Ti connected to any of the daisy-chained controllers can be accessed through any controller in the local network, thus facilitating communication by only having to fit one RS-232 modem for example.