Method and device for monitoring moisture related operating condition of an immersed solid dielectric material

Abstract

A method and device for monitoring, within an enclosure, moisture content level of a solid dielectric material, or paper, immersed in a dielectric fluid, or oil, both of which having respective moisture content, and known water solubility properties varying with temperature, and a corresponding bubble formation temperature. The device includes a moisture detector and a temperature detector for measuring the oil moisture content and temperature levels, respectively. A microprocessor, electrically connected to both the moisture and the temperature detectors, has the known water solubility properties of the paper and the oil stored therein along with the oil gas content level and the enclosure pressure related data and processes the oil moisture content level and the oil temperature level so as to determine the paper moisture content level and the bubble temperature. The latter being displayed on a display connected to the microprocessor.

I claim:  
     
         1 . A device for monitoring moisture content level of a solid dielectric material inside an enclosure and a corresponding bubble formation temperature within the enclosure, said solid dielectric material being immersed in a dielectric fluid, said dielectric fluid filling said enclosure, said solid dielectric material and said dielectric fluid having a respective moisture content, said solid dielectric material and said dielectric fluid having known water solubility properties varying with temperature thereof, said dielectric fluid having a gas content level thereof, said enclosure having pressure related data thereof, said device comprising: 
 a moisture measuring means for measuring moisture content level of said dielectric fluid;    a temperature measuring means for measuring temperature level of said dielectric fluid; and    an electronic circuit means for computing said moisture content level of said solid dielectric material and said corresponding bubble formation temperature, said electronic circuit means being electrically connected to both said moisture measuring means and said temperature measuring means, said electronic circuit means having said known water solubility properties of said solid dielectric material and said dielectric fluid stored therein, said electronic circuit means processing said fluid moisture content level and said fluid temperature level so as to determine said solid dielectric material moisture content level and said bubble formation temperature using said solid dielectric material moisture content level, the dielectric fluid gas content level and the enclosure pressure related data.    
     
     
         2 . The device of  claim 1 , wherein said electronic circuit means includes a displaying means for displaying said solid dielectric material moisture content level and said corresponding bubble formation temperature, said displaying means being electrically connected to said electronic circuit means.  
     
     
         3 . The device of  claim 1 , including an operator interfacing means for an operator to interface with said electronic circuit means, said operator interfacing means being electrically connected to said electronic circuit means so as to allow said known water solubility properties of said solid dielectric material and said dielectric fluid, the dielectric fluid gas content level and the enclosure pressure related data to be provided to and stored in said electronic circuit means.  
     
     
         4 . The device of  claim 1 , wherein said electronic circuit means is remotely electrically connected to both said moisture measuring means and said temperature measuring means so as to allow said moisture measuring means and said temperature measuring means to be located in a generally inaccessible location.  
     
     
         5 . The device of  claim 1 , including an operator interfacing means for an operator to interface with said electronic circuit means, said operator interfacing means being electrically connected to said electronic circuit means, said electronic circuit means providing a sensor location menu through said operator interfacing means so as to allow an operator to select a specific location of both said moisture measuring means and said temperature measuring means within said enclosure, whereby said specific location affecting determination of said solid dielectric material moisture content level and said corresponding bubble formation temperature by said electronic circuit means.  
     
     
         6 . The device of  claim 2 , including: 
 a second moisture measuring means for measuring second moisture content level of said dielectric fluid, said electronic circuit means comparing said first and second dielectric fluid moisture content levels and calculating a relative difference therebetween relative to said first dielectric fluid moisture content level, said electronic circuit means displaying on said displaying means either a warning message when said relative difference is equal or larger than a predetermined value or said solid dielectric material moisture content level and said corresponding bubble formation temperature when said relative difference is smaller than said predetermined value;    whereby said second moisture measuring means being a reference moisture measuring means to enable detection of malfunction of said device.    
     
     
         7 . The device of  claim 2 , including: 
 a second temperature measuring means for measuring second moisture temperature level of said dielectric fluid, said electronic circuit means processing said first and second fluid temperature levels and said fluid moisture content level so as to determine first and second solid dielectric material moisture content levels respectively, said electronic circuit means displaying on said displaying means an average of said first and second solid dielectric material moisture content levels and said corresponding bubble formation temperature.    
     
     
         8 . The device of  claim 7;  wherein said first and second temperature measuring means are located adjacent bottom and top regions of the enclosure, respectively.  
     
     
         9 . The device of  claim 2 , including: 
 a second moisture measuring means for measuring second moisture content level of said dielectric fluid, said electronic circuit means comparing said first and second dielectric fluid moisture content levels and calculating a relative difference therebetween relative to said first dielectric fluid moisture content level, said electronic circuit means processing said first and second fluid moisture content levels and said fluid temperature level so as to determine first and second solid dielectric material moisture content levels respectively, said electronic circuit means displaying on said displaying means either a warning message when said relative difference is equal or larger than a predetermined value or an average of said first and second solid dielectric material moisture content levels and said corresponding bubble formation temperature when said relative difference is smaller than said predetermined value;    whereby said second moisture measuring means being at least a reference moisture measuring means to enable detection of malfunction of said device.    
     
     
         10 . The device of  claim 1 , wherein the pressure related data includes a pressure level within the enclosure, and wherein said device further includes a pressure measuring means for measuring pressure level within the enclosure, said electronic circuit means being electrically connected to said pressure measuring means.  
     
     
         11 . A method for monitoring moisture content level of a solid dielectric material inside an enclosure and a corresponding bubble formation temperature within the enclosure, said solid dielectric material being immersed in a dielectric fluid, said dielectric fluid filling said enclosure, said solid dielectric material and said dielectric fluid having a respective moisture content, said solid dielectric material and said dielectric fluid having known water solubility properties varying with temperature thereof, said dielectric fluid having a gas content level thereof, said enclosure having pressure related data thereof, said method comprising the following steps: 
 a) measuring moisture content level of said dielectric fluid using a moisture detector;    b) measuring temperature level of said dielectric fluid using a temperature detector; and    c) computing said solid dielectric material moisture content level and said corresponding bubble formation temperature using a processor electronic circuit, said electronic circuit being electrically connected to both said moisture detector and said temperature detector, said electronic circuit having said known water solubility properties of said solid dielectric material and said dielectric fluid stored therein, said electronic circuit processing said fluid moisture content level and said fluid temperature level so as to determine said solid dielectric material moisture content level and said bubble formation temperature using said solid dielectric material moisture content level, the dielectric fluid gas content level and the enclosure pressure related data.    
     
     
         12 . The method recited in  claim 11. , including the step of: 
 d) displaying said solid dielectric material moisture level and said corresponding bubble formation temperature using a display, said display being electrically connected to said electronic circuit to receive said solid dielectric material moisture content level and said corresponding bubble formation temperature therefrom.    
     
     
         13 . The method recited in  claim 12 , wherein said display is remotely electrically connected to said electronic circuit.  
     
     
         14 . The method recited in  claim 12 , wherein step a) includes measuring a second moisture content level of said dielectric fluid using a second moisture detector; step c) includes said electronic circuit comparing said first and second dielectric fluid moisture content levels and calculating a relative difference therebetween relative to said first dielectric fluid moisture content level; and step d) includes displaying on said display either a warning message when said relative difference is equal or larger than a predetermined value or said solid dielectric material moisture content level and said corresponding bubble formation temperature when said relative difference is smaller than said predetermined value; whereby said second moisture detector being a reference moisture detector to enable detection of malfunction of said first moisture detector.  
     
     
         15 . The method recited in  claim 12 , wherein step b) includes measuring a second moisture content level of said dielectric fluid using a second moisture detector; step c) includes said electronic circuit processing said first and second fluid temperature levels and said fluid moisture content level so as to determine first and second solid dielectric material moisture content levels respectively; and step d) includes displaying on said display an average of said first and second solid dielectric material moisture content levels and said corresponding bubble formation temperature.  
     
     
         16 . The method recited in  claim 15 , wherein said first and second temperature detectors are located adjacent bottom and top regions of the enclosure, respectively.  
     
     
         17 . The method recited in  claim 11 , including the step of: 
 d) sending said solid dielectric material moisture content level and said corresponding bubble formation temperature to a remote unit so as to allow post-processing thereof, said remote unit being electrically connected to said electronic circuit.    
     
     
         18 . The method recited in  claim 11 , including after step b) the step of: 
 b1) providing an operator interface so as to allow said known water solubility properties of said solid dielectric material and said dielectric fluid, the dielectric fluid gas content level and the enclosure pressure related data to be provided therethrough; said operator interface being electrically connected to an electronic circuit for an operator to interface therewith and store said known water solubility properties of said solid dielectric material and said dielectric fluid, the dielectric fluid gas content level and the enclosure pressure related data therein.    
     
     
         19 . The method recited in  claim 18 , wherein said operator interface is remotely electrically connected to said electronic circuit.  
     
     
         20 . The method recited in  claim 11 , including after step b) the step of: 
 b1) providing an operator interface electrically connected to an electronic circuit for an operator to interface therewith, said electronic circuit providing a detector location menu through said operator interface so as to allow an operator to select a specific location of both said moisture detector and said temperature detector within said enclosure, whereby said specific location affecting determination of said solid dielectric material moisture content level and said corresponding bubble formation temperature by said electronic circuit.    
     
     
         21 . The method recited in  claim 12 , wherein step a) includes measuring a second moisture content level of said dielectric fluid using a second moisture detector; step c) includes said electronic circuit comparing said first and second dielectric fluid moisture content levels and calculating a relative difference therebetween relative to said first dielectric fluid moisture content level, said electronic circuit processing said first and second fluid moisture content levels and said fluid temperature level so as to determine first and second solid dielectric material moisture content levels respectively; and step d) includes displaying on said display either a warning message when said relative difference is equal or an average of said first and second solid dielectric material moisture content levels and said corresponding bubble formation temperature when said relative difference is smaller than said predetermined value; whereby said second moisture detector being at least a reference moisture detector to enable detection of malfunction of said first moisture detector.  
     
     
         22 . The method recited in  claim 11 , wherein the pressure related data includes a pressure level within the enclosure, and wherein step a) includes measuring a pressure level of the enclosure using a pressure sensor; step c) includes said electronic circuit being electrically connected to said pressure sensor.