Method for determining dissolved gas concentrations in dielectric coolants

Claim 2

A power transformer comprising, in combination: a transformer tank containing a non-condensable gas and a liquid; a transformer core and winding disposed within said tank in thermally coupled relation with the liquid; a sight glass in fluid flow relation with the interior of said tank for containing an observable sample of the liquid; heater means in thermal relation with said sight glass for heating the liquid sample to cavitation; pressure indicating means coupled with said tank for determining the pressure of the liquid sample; and temperature indicating means proximate said sight glass for determining the temperature of the liquid sample; whereby the concentration of the non-condensable gas dissolved in the liquid can be determined by noting the temperature and pressure of the liquid sample at the onset of cavitation.

Claim 3

A gas-insulated transformer comprising: a transformer tank containing a noncondensable gas for use as a dielectric insulating medium; a plurality of transformer windings arranged around a transformer core within said tank; a plurality of tubes extending through said windings and containing a liquid coolant for cooling said winding during transformer operation; piping means connecting with said coolant tubes and with a heat exchanger for carrying said coolant to said heat exchanger and removing heat from said coolant; a sight glass connected with said piping means for observing a sample of said coolant within said piping means; a pressure indicating means connected with said piping means for determining said coolant pressure; heater means in thermal contact with said sight glass for heating said coolant to cavitation within said sight glass; and temperature indicating means thermally proximate said sight glass for indicating the temperature of coolant within said sight glass.

Claim 4

A gas-insulated transformer comprising: a transformer tank containing a noncondensable gas for use as a dielectric insulating medium; a plurality of transformer windings arranged around a transformer core within said tank; a plurality of tubes extending through said windings and containing a liquid coolant for cooling said winding during transformer operation; piping means connecting with said coolant tubes and with a heat exchanger for carrying said coolant to said heat exchanger and removing heat from said coolant; a sight glass connected with said piping means for observing a sample of said coolant within said piping means; a pressure indicating means connected with said piping means for determining said coolant pressure; heater means in thermal contact with said sight glass for heating said coolant to cavitation within said sight glass; and temperature indicating means thermally proximate said sight glass for indicating the temperature of coolant within said sight glass.

Claim 5

The transformer of claim 2 wherein the coolant comprises a halogenated hydrocarbon.

Claim 6

The transformer of claim 2 wherein said noncondensable gas comprises sulfur or carbon hexafluoride.

Claim 7

The transformer of claim 2 wherein said heater means comprises a plurality of turns of resistance wire around said sight glass.

Claim 8

The transformer of claim 2 wherein said temperature indicating means comprises a thermocouple.

Claim 9

A vaporization cooled transformer comprising: a transformer tank containing a condensable liquid coolant; a transformer core and winding within said tank for contact with said coolant; a heat exchanger connected with said tank for receiving said coolant in vaporized form and returning said coolant in condensed form; an expansion tank connected with said transformer for isolating said noncondensable gas from said coolant during transformer operation; a sight glass connected with said tank for providing visual access to said coolant; heater means in thermal relation with said sight glass for heating said coolant to cavitation; pressure indicating means connected with said transformer for determining said coolant pressure; and temperature indicating means thermally proximate said sight glass for determining the temperature of said coolant.

Claim 10

A vaporization cooled transformer comprising: a transformer tank containing a condensable liquid coolant; a transformer core and winding within said tank for contact with said coolant; a heat exchanger connected with said tank for receiving said coolant in vaporized form and returning said coolant in condensed form; an expansion tank connected with said transformer for isolating said noncondensable gas from said coolant during transformer operation; a sight glass connected with said tank for providing visual access to said coolant; heater means in thermal relation with said sight glass for heating said coolant to cavitation; pressure indicating means connected with said transformer for determining said coolant pressure; and temperature indicating means thermally proximate said sight glass for determining the temperature of said coolant.

Claim 11

The transformer of claim 7 wherein said coolant comprises a halogenated hydrocarbon.

Claim 12

The transformer of claim 8 wherein the halogenated hydrocarbon comprises a chlorinated fluorocarbon.

Claim 13

The transformer of claim 9 wherein the chlorinated fluorocarbon comprises trichlorotrifluoroethane.

Claim 14

The transformer of claim 7 further including a noncondensable gas.

Claim 15

The transformer of claim 7 wherein the noncondensable gas is selected from the group consisting of carbon hexafluoride, sulfur hexafluoride and air.