Siemens allows for the detection of faults inside high-voltage transformers

Siemens Industry Inc., Automation & Drives Technologies, (Atlanta, GA; SE&A) has introduced a new Partial Discharge Monitor that can detect faults developing inside high voltage transformers before they lead to problems that can prematurely retire the units. Such faults may be caused by aging components, mechanical malfunction or overloading.

One of the most common failures in transformers is due to the erosion of insulation material. "Transformer malfunctions, particularly those due to a deterioration of the insulation, are a growing concern," said Kris Goly, reliability maintenance manager at Siemens Westinghouse Technical Services, the service arm of SE&A. "The average age of a transformer that fails due to insulation problems – specifically from heat, oxidation, acidity, or moisture – is 17.8 years, well below its life expectancy of 35 to 40 years."

A unique feature of the Partial Discharge Monitor is its ability to detect faults inside the transformer, pinpointing where in the unit the fault has occurred. The monitor uses up to four ultrasonic and radio frequency sensors housed in special heads to monitor disruptions so that utility and large industrial customers can schedule repairs before they become expensive or require equipment/plant shut-down.

While other methods of monitoring transformers do exist, monitoring the transformer from the interior is new. Previously developed techniques monitor the transformer bushings (exterior) or the oil, but these methods fail to direct repair personnel to the place within the unit where the repair needs to be made.

Edited by Jerry R. Borland, P.E.
Managing Editor, EC Online