Why is water killing power transformer insulation?

Whenever we talk about life on earth, the first element that comes to our mind is water. Besides oxygen, water is the primary element that aids in sustaining life on earth. While humans and other living organisms derive life from water, certain aspects lose their life to water. Here we are talking about the oil-paper insulation in transformers. Water squeezes out the insulating capacity of transformers.

Inclusion of Water in Power Transformers

The oil-paper insulation includes the various elements of pressboard and paper that facilitate the insulation’s mechanical stability. Cellulose happens to be the major component of pressboard and paper. Glucose molecules are an integral of the paper insulation that forms a chain after linking. 1200 is the average count for some molecules present in the cellulose chain. Such large chains inject the mechanical strength of the Chint Power Transformers for fixing the windings. The Chint power transformer derives the necessary power even when conditions are rough, like that of a short circuit.

Water molecules are responsible for breaking the chains by reducing the mechanical force between the insulating elements. Even if the paper gets completely dried, there would still be some moisture within the transformer. Considering higher temperatures, the water molecules facilitate the splitting of chains, leading to short-chain lengths, with the greater amount of water being the by-product. Here a self-accelerating procedure begins where Chint transformer insulation’s mechanical stability faces a backlash. 

The speed of the procedure depends on the moisture content of the transformer and the water content in the insulator. Experts analyse the life of a transformer to be at its end when the average length of the chain paper is 200 or below. The transformer loses its capacity to deal with mechanical stress as its mechanical strength decreases.

Age happens to be a determining factor in a transformer’s moisture content. Experts claim that the more the water molecules are in a transformer, the more aged it is. The age would be a determining factor concerning the renovations required by the transformer and the days for which the transformer is workable. When a partly-wet transformer comes into consideration, one can easily dry up the moisture and increase its overall lifespan. Provided the water happens to be extremely wet, even un-drying won’t help reduce the power transformer’s age.

Finding Out The Moisture Determination via Dielectric Frequency Response

The Dielectric Frequency Response analysis is the most reliable way of finding out the moisture content within a power transformer. The dielectric features like conductivity, dielectric losses, and capacity get altered when the material absorbs water. 

The principle of measurement 

Whole of the main transformer features a humidity sensor for the dielectric moisture analysis of the power transformer. The measurement device gets connected with the bushing of the power transformer and helps determine the insulation’s dielectric properties. Once the insulation has a measurement, the connection becomes a child’s play. 

Reduction in time for DFR Measurements

The Traditional method of measurement via FDS

Under normal circumstances, the dialectic parameters get measured in the frequency domain by applying diverse frequencies and response measurements. This technique is known as Frequency Domain Spectroscopy (FDS) and finds applicability across the various hertz areas until GHz and above. 

The Conventional Method of measurement via PDC

The PDC or Polarisation depolarisation current measurement refers to measuring dielectric properties via voltage step application to the tested asset. Measuring the result polarisation current for a while is another necessity. When one uses PDC instead of FDS, the time required for measurement reduces considerably.

Modern Devices For Measuring DFR

The higher complexities regarding the DFR measurement are a massive hindrance in the measurement. The modern DFR measuring software holds the aptitude to automatically set the frequencies for every power transformer. The adjustment begins with the maximum frequency set-up that gradually reduces to the necessary frequency after a thorough assessment. The automated assessment technology eclipses the age limitations, oil conductivity, and geometry. 

Thus one must understand how water is an influential deterrent for powered transformers. The goal is to apply the various methods available to keep the moisture content at bay and allow the transformer to thrive. Thus one must understand how water is an influential deterrent for powered transformers. The goal is to apply the various methods available to keep the moisture content at bay and allow the transformer to thrive.

By sameer

Leave a Reply

Your email address will not be published.

error: Content is protected !!