S-03
S-03: Description
Introduction
The continuous filtration of tap-changers of power (main) transformers is generally focussed on the reduction of the internal contamination of its oil inventory caused by :
- particles
- moisture
When an on-load tap-changer works under load the dirt is always internally generated causing an increase in mechanical wear and a reduction of the dielectric strength of the oil as a consequence.
The another very unpleasant decrease of the dielectric strength of a switching oil is simultaneously caused by the moisture, because two potential sources of the water in the tap-changer always exist :
- internal - as a by-product of the arc-induced decomposition of the oil.
- external – due leaking of the air filter or conservator
The S-03 fitration unit was developed to handle a very new problem of recent versions of tap-changers built from non-hydroscopic (hydrofobic) insulants.
Hydrofobic insulants, on the contrary to the previously used hydroscopic materials (as e.g. boards) of „old“ tap-changers, do not have any „buffer capacity“ to the water - they are not able to bind the water from the oil.
Therefore any little amount of the water which enters into the oil inventory of a modern „hydrofobic“ tap-changer immediately increases the relative humidity and decreases the dielectric strength of the oil.
Users of „hydrofobic“ tap-changers are therefore exposed to a new and very uncomfortable operational reality.
While old „hydroscopic“ tap-changers were able to withstands the slight water contamination for relatively long time without the critical loss of the dielectric strength, the dielectric behaviour of modern tap-changers is very sensitive to any water input and the user is therefore forced to continuously remove the water and/or a dirt from his tap-changer to prevent the decrease of the dielectric strength of the oil.
The S-03 filtration unit, working continuously, satisfies both requirements by means of the external collection of the undesired substances.
The large-volume of the pre-dried cellulose insert simultaneously binds the water and dirt particles for relatively long time without negative impacts on the reliability of a tap-changer.
Basic advantages of the S-03 filter unit
- the long-term preservation of the required dielectric strength of the oil
- the reduction of the wear of mechanical parts
- the reduction of costs due to prolonging of maintenance time-intervals
- the strong reduction of the number of oil replacements = cost reduction
- easy change of the filter insert under normal operational conditions.
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