Patent ID: 9026374
Filing Date: 2015-05-05
Classification: G01N,H01F

Abstract:
1. A method for determining the relative humidity of an insulating liquid filled electric apparatus, the method comprising the steps of: providing a container containing insulating liquid and gas, a communication unit providing communication between the gas of the container and gas of an external environment, and dehydration of gas passing through the communication unit: providing an electric unit and enclosing the electric unit within the container such that the electric unit is completely submerged within the liquid and below an interface between the liquid and the gas of the container; continuously measuring by a sensor and storing by a computing unit a measurement of the relative humidity of the gas in the container, calculating by the computing unit an average value of the relative humidity of the gas based on said stored humidity measurements during a certain time period, and determining by the computing unit the relative humidity of the insulating liquid based on said average value of the relative humidity of the gas and a relationship between the relative humidity of the gas and the relative humidity of the insulating liquid at equilibrium.