Patent ID: 7040138
Filing Date: 2006-05-09
Classification: G01N

Abstract:
1. Method for monitoring dissolved gases in liquid-filled high-voltage installations comprising a sealed separating vessel communicating via a first feeding pipe with a liquid tank of the high-voltage installation, wherein the liquid tank is connected with an oil conservator via a pipe, including the following steps: a) filling the separating vessel via the feeding pipe with the liquid from the liquid tank, wherein, due to the static column of the liquid above the feeding pipe, the liquid can flow from the liquid tank into the separating vessel, b) maintaining an equilibrium state between the liquid and the gas phase in the separating vessel by keeping the liquid level at a predetermined height through pumping off the liquid with a pump, wherein the pumped off liquid is fed back to the liquid tank or to the oil conservator, c) short-term leaving the equilibrium state by interrupting the pumping action or by reducing the pumping performance so as to increase the liquid level in the separating vessel, d) analyzing the gas above the liquid level in the separating vessel by e) feeding undissolved gases via a second feeding pipe into the gas phase above the liquid level in the separating vessel, f) monitoring the temporal change of the analyzed values, and g) evaluating the temporal change of the analyzed values for determining the origin of the undissolved gas wherein undissolved gases are discharged into a gas collecting vessel via a gas pipe branching off from the feeding pipe, and a gas sample is withdrawn from the gas collecting vessel after step b.